CNC Plasma, and potential laser cutting/plasma projects

Cool Stuff in Numerical Control Programming Class

I've been assigned to come up with some maintenance documentation for the Plasma CNC we have at our school. It is obvious that it isn't used much. The documentation for the torchmate 2 system is nicely done. I believe it was a previous senior project from a kit, and it's obvious the students did a wonderful job setting it up.

Today, I had the opportunity to start the machine up (after carefully reading the documentation) and jog the x and y axis around. I'd like to measure the kerf sometime soon to document that.

I eventually will need to come up with a sample part that my professor will be able to easily demo to prospective students. So i'm trying to come up with ideas for that. Here are some neat links with great ideas and source files:

http://www.cnczone.com/forums/showthread.php?t=5276

http://www.cnczone.com/forums/showthread.php?t=19346

In my research about the CNC plasma cutters I've stumbled across a wealth of resources that I wish I had time to dive into right now.
http://www.cncinformation.com/advanced-robotic-tech-cnc-plasma-cutter-videos/

which has a variety of videos talking about CNC plasma cutting.

I signed up for a yahoo group where I was able to find a majority of these resources from:
http://tech.groups.yahoo.com/group/plasmacutting/

Getting involved

Whether it is a detrimental thing or not I'm getting involved in two more clubs at my school.

• Mars Reach
• Society of Manufacturing Engineers

The mars reach club does high altitude balloons, rocketry, and a few other things. SME may let me do some community service with some of the engineering knowledge i'm learning at some local schools. Which actually sounds cool to me. I always loved teaching children at OMSI, and cybercamps.

I've been researching high altitude balloons for taking atmospheric pictures like the one below(100,000 feet.) I am very excited about it. I am timid to commit too much time though as I have plenty of schoolwork and other projects going on at the same time. I just made a personal decision not to let good opportunities pass me by. "Reach for the stars" so to speak.



Image from http://www.natrium42.com/halo/flight2/#hardware

Here is some of the fruits of my research:

1. http://vpizza.org/~jmeehan/balloon/
2. http://www.universetoday.com/2006/01/20/satellites-on-a-budget-high-altitude-balloons/
3. http://hackaday.com/2009/09/19/high-altitude-balloons/
4. http://www.natrium42.com/halo/flight2/#hardware
   
5. http://www.arhab.org/

On a seperate topic - i stumbled into this engineered nerf gun esque thing. http://boltsniper.com/BS-5/BS5.htm pretty slick. He calls it a FAST-ACTION RIFLE(FAR).

So for now I'm just going to try and stay on top of things, as they just keep piling up, and i keep knocking em down at about the same rate. Kind of a good and bad thing. *shrug* at least it's progress. Onward!

Schoolwork update

I've been busy with school specifically ethics and micro-economics as they have been assigning nearly daily assignments of varying difficulty. While this is all going on we did a neat lab in Numeric Control Programming a week or two ago. The pictures show what i was able to accomplish with hand coding some g-code. I was limited because of time, and I wanted to do a much more elegant part, but had to settle for this.

Troy sent me the spindle model. I've been working on a similar part for our numeric control programming class as well, which i finished coding today. It was much more involved that the previous as i had to code in the rough and finishing pass, there was a lot of math involved to ensure clearance distances for the part were appropriate. Either way the lab assignment will help fabricating the spindle for the CNC machine that much easier.

Here's what the CNC lathe simulation for my Lab looks like:

Research of various CNC machine/gantries

This guy has a similar build to ours. I'll be supplementing this list as i continue my research.

http://www.cnczone.com/forums/showthread.php?t=27527
What's interesting is he also is using 80/20 extrusion, ballscrews, and 425 oz-in steppers. His is a router build, so we have the complicating element of the head design. I don't know what i'm going to do about the Z-axis still. He also mentioned his z-axis having trouble lifting the 28 pounds, i'll have to look into that more, and consider it for our head design. Interestingly for a home switch, he uses a .25" thick piece of aluminum with current to arc current through and accurately determine if the head is @ zero.

More to come...

Spring Design

I recently have been discussing spring design with a fellow named Shredder. While I did this last year I was able to apply some of the concepts i've learned from Machine Design II.

http://www.airsoftretreat.com/forums/index.php?topic=82508.msg808447#msg808447

There are some screenshots of what i was able to do with the data. I'd like to verify the forces with weights to see what force the springs are generating so i can correlate it to the theoretical force generated based on the spring geometry. I'm sure it's off - i just don't know by how much.

Shredder wants to make a 1000 fps airsoft rifle. So naturally increasing spring force is a good place to start. I was inquirying how he made some of his springs and learned that i may be able to do it too!

Here's the reference information:
http://shredderscs.proboards.com/index.cgi?board=projects&action=display&thread=80&page=1
http://home.earthlink.net/~bazillion/tooling.html
http://home.earthlink.net/~bazillion/Coiler/index.html
http://home.earthlink.net/~bazillion/compression.html#tweaks

While researching spring mfg processes, I ran into this useful fellow who seems to be adept at metalworking. He also has some useful tube cutting techniques could be useful for HPV.
http://metalgeek.com/

Focus shifting back to the CNC

With daily homework from ethics and micro-econ keeping me at bay, I have little time to focus on the classes i really want to pour my heart into - CNC class and manufacturing planning.

I am shifting my extra-curricular focus back to completing the CNC machine. There are two major issues to tackle at this point:

-Research, and Redesign frame for rigidity (likely a Gantry setup build)
-Consider, select, and integrate head design (we don't know whether we will build troy's spindle or buy an aftermarket solution)

I previously was concerned with opto-isolation, but after this forum post on cnczone I'm not as concerned with it. I will do what is called common grounding/bonding which is as described in the thread involves using the same ground for both the computer and stepper powersupply circuit. It is rumored that this helps remove noise interference issues by making both the same potential. http://members.cox.net/pc-usa/station/ground3.htm


I'm doing research on the various gantry configurations others are using and considering ballscrew/rail placement. The technical difficulty i'm facing is that we selected such a large z-axis. This means it may look like a tower when it's done... Hmm more on this as i find things out.

http://8020cnc.com/cnc%20pics

Back to homework!

Another quick project

My professor was telling me how he needed to make a projector mount, so I decided to jump on the project. I must be getting more proficient at SW because here's what I got after about 2 hours of work. I put some gaps underneath to allow the projector to breath. The actuating device is simply two bolts, I didn't model them. Although, I hardly think that is necessary to convey the design concept. Some specifics aren't on the model, but can be easily added (the bolt pattern for the bottom of the projector.)

It was fun. Time for sleep.

Low cost Laser engraver

My friend bryan found this little gem.

http://www.instructables.com/id/60-Laser-Engraver--Cutter/

The guide shows how to make a pantograph; which is a device that lets you mimic hand movements in 2D exactly using a mechanical device. Kinda cool, i wonder what other applications they could have.

There is rumor that you could hook the laser up in place of the ink-cartridge, and turn a printer into a laser engraver/cutter. Frankly, I don't think it will be powerful enough for good work. I'd probably go with a 60 Watt CO2 laser if i was to build one myself.

Very cool nonetheless.

By the way nasa is cool :) Perhaps some future CNC projects...
http://www.nasa.gov/multimedia/3d_resources/3d-models-gallery.html

Waterproofing electronics

I was doing some research on solenoids for a new"ish" project, (more just exploring possible future projects) and I stumbled across a bit on waterproofing servos for robotics. Now this is marginally interesting except that I'm sure that the methods they are using would apply to other electronics.

http://www.societyofrobots.com/actuators_waterproof_servo.shtml

I'm thinking about waterproofing my ipod nano for swimming. Liquid Tape sounds like a possibility... Anyways, rest time.

Making a difference FEELS GOOD

I have found my calling in life. I love using my mind to make things better for other people.

While airsoft isn't the most noble of causes, it has shown me what a wonderful feeling it is to accomplish the bolded sentence above. My most recent success has been in the airsoft business though. I've developed a simple product to enhance the precision of a particular type of airsoft sniper rifle.

http://www.youtube.com/watch?v=lgjwU_fhXoY

This video shows what that product is. I've kept it at a reasonable price for both the consumer, and myself. It's interesting to see how my Microeconomics class is applying to my small business, it is helping me identify supply and demand curves to get the optimal price point. Yet again, my education is really enhancing helping me be a better engineer.

Anyways, my excitement is due to the fact that I've received some great feedback from several users. While I had conducted several tests before releasing my product, it took a long time to start getting some user feedback. As everyone's rifle has different tolerance, I feared compatibility issues. I had to make some tough judgment calls about dimensions, and I seem to have made the right decisions, due to the feedback coming back.

My product has actually made a substantial improvement to the airsoft sniping community! I'm ecstatic!

Online Engineering, with Online Partner
This is only the beginning, I've been working on a project with a handy nice fellow named Noobie on the forums. We have been working together to pool our resources, and develop a complete kit that incorporates our individual components. I anticipate that we will release it very soon.

http://www.airsoftretreat.com/forums/index.php?topic=86871.0

I have great respect for him, as he is easy to work with, and humble. Rare attributes to find in an engineering team. He is a skilled machinist, and generally knowledgeable about anything. He makes these trigger systems individually. So he is very skilled at prototyping.

Lastly, I modeled his trigger system for future development. Further developments of that are in the far future...


Modeled from:



Most importantly among all these projects. I'm learning a great deal about myself in terms of engineering. I'm like a locomotive... When I get rolling there's no stopping. :) Unless of course a girl gets in the way... LOL

No but really, I don't care if it's airsoft, automotive, aeronautics, a household appliance. It's clear to me now. I love using my brain to make the world a better place for others. And if I have to jump a few difficult hurdles to achieve that goal so be it. Bring it on!

Back to school! Hiatus

Hey folks!

I've just started the school year off again, and things are getting busy. I have the CNC project looming over my head, which I anticipate will pick up speed in a few weeks to a month because I am waiting to get permission to use the good equipment in the shop. I also have to wait till my folks, bring the various CNC components down. Right now I think our team is dang close to our initial budget estimate. This makes me happy :) We have 300$ left, and I anticipate a little over 500$ for all the frame components. I want to account for the "mistake" factor as an additional 200$, I'm sure tooling will take a bit too.

I have started a fairly involved project with my Mfg Analysis & Planning class. Joe has brought in a local business masalaspices for us to work with. We are acting like a consulting firm would and helping them make their business more efficient. I'm sure it will provide us with some invaluable real world experience.

My Numerical Control Programming course is looking to be very exciting! It's really building on all the things I've learned this summer. We'll see how it goes! I'm really going to focus on excelling in this class, as it is developing into my passion. I feel like a kid at disneyland in that class, while some of my classmates have trouble staying awake. lol. They don't realize how powerful what we are learning is... Muahaha

I'm figuring out shipping logistics while at school here for my small airsoft business as well. I developed a few new unique products that are under a healthy demand. So i'll have to stay on top of that while doing all the classes and projects.

I've signed up for an exercise class with some friends, so I'm going to try and stay physically and mentally fit this term. I just need to be careful not to add anything more to my plate (which i love to do...) With that in mind, I'm going to put this blog on a low priority. I really want to have a successful term in every way. That's why I won't be as active on this. Sorry!

Annotating links + electrical issues.

Because, this blog has been so useful at keeping me on track with tasks, i'm going to lay down a few things for my own references:

Troy wants me to do stellar electrical wiring, so he referenced me to:
http://workmanship.nasa.gov/guidadv_recmeth_wusplice.jsp

Electrical Problems to tackle:

Opto-isolation
We are also discussing the prospect of integrating Opto-isolation into the circuit. From what I read on http://www.epanorama.net/circuits/parallel_output.html#circuithow the introduction references that simply installing a PCI Parallel port card should protect your motherboard from frying. Troy makes the good point that just because there is a card that it doesn't protect your PCI bus. (sadface) But from Newegg at 15$, it's not a steep price in the offhand chance that the guy is right. Maybe some inspection of the components of the card would do the trick, or questioning folks on CNCzone may do the trick as well.

http://www.newegg.com/Product/Product.aspx?Item=N82E16815166006
http://www.newegg.com/Product/Product.aspx?Item=N82E16815166007

Wiring in the CNC4PC controller.
Since Mach3 functions through the parallel port only (i think.) We cannot use the RJ45 port to control spindle speed (i think - i must verify this.) As such that means we will have to wire in that board into the specific pins we decide on the parallel port. Naturally, this means we will have to make our own circuit for this purpose. The interesting bit, is that we can integrate the opto-isolation components at this phase (hopefully.) The first 7 pins are reserved already so we are going to using the next couple pins for 6 limit switches (which I just bought from Fry's at 2$ a piece,) an estop button, and then finally the spindle control com pins.

Voltage Drop
Lastly, we need to figure out how to voltage drop from 49VDC to 36VDC to make full use of the steppers, currently we are at 24VDC. So our blunder of not accounting for Vrms of the toroid transformer is causing us problems. Fortunately, with the 18VAC line, we get 24VDC through the rectifier/cap. So we are at least functioning, and without opto-isolation. We considered using a bunch of resisters for a moment, but it looks like we would need literally about 100 to do the job. Frankly, that is not acceptable. Another option is to simply buy another toroid transformer with different output. I wish I had tried harder in fundamentals of electrical circuits. Now I must research more. Oh well, lesson to be learned, do well in school! Always! LOL.

CNC update: Skipped steps fixed, ballscrews in

Fixed Stepper missed/skipped steps

With my fixed 2500+ AMD desktop I was able to hook up and test the control board again. A drivertest of the parallel port showed that the computer could provide a steady 25 khz waveform. In fact is was around 26 khz for the test, not really sure why, but it was consistent and as such yielded a solid line with very minor blips in the waveform. I did have the system tuned in the services and applications down to a measily 14 processes in windows XP. So basically, the system was running bare bones.

With the breakout board hooked up, along with the steppers, I was able to move them around smoothly with mach3. Compare the video with the older video where you can visibly see the steppers doing wierd things.

http://www.youtube.com/watch?v=ywBT3VNERIg

Ballscrews in!

I also went to pick up a package from USPS, because they needed a signature and no one was at the door when they arrived at my house. I picked them up and was surprised to see the packaging a bit damaged. I was also concerned that something might have fallen out.

Frankly, I was hoping the ballscrews would have been protected a little better. Oh well, to get those three complete ballscrews with bearings for 375$ shipped is a downright steal. The value well makes up for it.

The condition of all the components was agreeable. The threads on the ballscrew were a little rough, which looked like my first attempts at threading something in my machining class. I'm sure they will do the job of securing the ballscrew though. Surprisingly, some of the bearings were NSK! High quality stuff! Unfortunately, I don't think the angular contact bearings are though - they were some other unknown brand. I'll have to look into that later.

The end machining is the feature i'm most concerned with. The NSK bearings simply wouldn't go on the shaft. They were too tight. I measured them to be something like 9.91 +/-0.01mm and the end machining came in at about 9.99 +/-0.01mm. I think I may have to chuck them up in a lathe and use some emery cloth, or sandpaper to bring them down to an acceptable size. I don't feel like bashing the bearings on with a hammer. Something just doesn't feel right for an interference fit. The stepper couplers are interesting... They look like they will work great with set screws. The interesting bit is that they expand/contract vertically, but they do not twist at all to lose precision. Clever.

With the prospect of machining the ballscrews further, I was concerned about leaving the ballnuts on the ballscrews. From a quick search of cnczone I found this:

http://www.cnczone.com/forums/showthread.php?t=86614

From this thread I've learned that you can remove ballnuts by using a mandrel to hold the balls in place. I also learned that i probably don't need to remove the ballnuts from the ballscrew to machine them. Yay, I like it when things follow the KISS principle. I am contemplating how I will stabilize the ballscrew in a lathe. I'm thinking a live center should do the trick, I just don't want to have to drill the end of the ballscrew for that purpose. I do know they have those brass triple finger support type things (forgot the name) which may do the trick, I just don't want to risk damaging the screw. Perhaps more research is in order about chuking up a ballscrew for machining.

The Beach Boys FTW

I saw THE beach boys this weekend at Chinook Winds Casino today. Don't worry, I didn't spend a dime on gambling. The main singer sounded exactly like you hear on the radio, it's amazing. His voice is unreal. Ok! Back to engineering stuff.

Stepper Problems
I've begun researching why there were weird things going on with the steppers as you can see in the youtube video in the previous post. CNCzone.com is where i've begun my quest for knowledge. I previously thought it was resonance, but after a cursory read I don't think that is what is going on. I suspect that the steppers are missing steps, or skipping them due to the slow 750 mhz computer. Here are some relevant links about steppers:

- Making Steppers run reliably
- Stepper resonance

==================================================
Old computer and Overclocking
I intend to restore my old desktop computer to it's former glory(dead OS harddrive) and see how well that drives the stepper motors. I suspect if anything it will help to have a faster computer anyways :) It has a laptop processor 2500+ in it, that I used to overclock to about 3200+ speeds. (The laptop CPU's used to be renowned for the overclockability)

When AMD made a batch of processors they would go through and test and catogerize processors. The laptop processors were required to run reliably 1.833 ghz at 1.45 volts, they would seperate these "good" processors from the other "average" processors that would run reliably at 1.833 ghz at 1.65 volts. The "average" processors were then labeled as desktop processors. They are the exact same processors, pin's and all. So somebody akin to this knowledge would *cough* *cough* me - would purchase the laptop processor for the exact same price throw it in their desktop system, and raise the voltage to 1.65 volts (since all those processors were rated for the same max voltages.) Raising the voltage .2 volts lets you overclock quite a bit. With a healthy heatsink I was able to squeeze an extra 367 mhz with just those extra .2 volts on air cooling, and maintain the exact same stock temperature of about 39'Celsius. That would put the effective performance at the equivelant 3200+ processor (2.2 Ghz). So basically you get a 3200+ upgrade from a 2500+ for free! Woohoo! The highest I ever pushed it was 2.4 ghz - The temp's and voltage were too high for me to comfortably run it for any period of time though.

====================================================
Airsoft PartsI also went to the shop and updated one of my airsoft part's dimensions, and cranked out 248 parts. I'm trying to prepare a healthy stock for while I am at school I will not have access to a laser cutting machine. I probably will make my way over to the shop a few more times this week to crank more out, and move other projects along.

CNC BallscrewsI hope the ballscrews from ebay come in this week. I'm amazed at the price we got them. A quick comparison to roughly equivelant ballscrews off of Mcmaster showed that it would cost 3000$ for equivelant, mounting blocks, bearings, ball nuts, etc... Not to mention they have more than twice the tolerance (this is a bad thing lol.) The C7 ballscrews, ballnut, mounting blocks, bearings, etc.. All costed 375$ shipped. Yay ebay! Talk about savings...

Organzing Your Desktop

In any event, I spent 15 minutes organizing my desktop into appropriate folders because i simply have too many projects. This made using my computer much easier to navigate :) I suggest you do the same.



CNC Status
I promised I would get more pictures up, so here's a good one. It's the current build of the CNC machine we are building. I think we may need to change it over to a gantry style CNC. I need to sit down and see if I can run some calculations to determine if the Z-axis will be rigid enough, and if the HSR rails can take the load. While i could be mistaken, I recall some arbitrary number that the rails could handle being around 1200 lbs.

I am proud of what we have accomplished with the CNC machine so far. As we are quickly aproaching a linear moving, computer controled system, I look at our project with caution. As I am going back to school in a week, I will have to take the components down with me and finish off the machine by myself - which isn't a simple prospect in of itself. The logistics keep cropping up problems.

A preliminary assesment puts the frame cost around 500$, while we could make it lower cost, we are looking to make a rigid, precise, modular system that will allow upgrades in the future. As such, the design is oriented for the future the cost accordingly goes up. It also means - I will likely have to make the spindle. Eeep. Thankfully our school has excellent machines for the task.

My goal for our team is to get all the electrical components, flawlessly interfaced with the computer and Mach3 before I head down for school. While we have the 3 steppers interfaced, there still is the skipped steps to address, and tuning up a computer for the CNC; there still remains the task of getting a powersupply working for the treadmill motor, hooking it up to the CNC4PC board, and interfacing that board with Mach3. A big, but reasonable goal. Even if it doesn't work out this week, we are all patient, and want to do this well and correctly.

Engineer on!

It's Alive!!!

After buying a new Straight Thru DB25 M/F cable from fry's 4.99$ (again) and fiddling with mach3 configuration I was finally able to get movement!

After I bought the cable i came right home, plugged it in and attempted to run it. It didn't work. A moment of fear occured because I thought I had not identified the problem properly. I had to disable the E-stop, ensure the pins were sending the right signals according to the provided documentation, AND make sure they were assigned to the active motor port. So i had to change six different 0's to 1's, and assign pin numbers again. No biggie, after that the X stepper moved after a G0 X2 command! Yay.

I quickly recorded a video:
http://www.youtube.com/watch?v=ay-3UZTvABA

I was so caught up in the moment I didn't really notice the resonence, or the missed steps on the steppers. So that is the next hurdle to tackle, but at least all the steppers are moving in the direction I want them to :)

This CNC machine is proving to be like a child. You pour in love, pour in love, and get little back, but when you do get something back it is soooo rewarding. (not that I am an expert on children by any means.) So after a bit of tuning, the focus will shift to the CNC4PC board, and getting the spindle motor working as we want.

I also need to clean up the powersupply case, properly mount the control board, cut up some wire so we can easily attach the steppers where they ought to be on the actual machine. I'm not entirely sure on the layout we will take, but given enough time I'm sure we will find a solution. This was definitely the hurdle I feared most about this project, but it is quickly resolving down to the simple mechanical aspects, and money.

More to come later. I still owe you some pictures too.

Serious CNC Progress

Sorry I haven't posted any updates in awhile. Women. lol.

We've received our CNC4PC board in the mail, it was delayed cause they were out of stock. It will control the spindle, it is controlled by an RJ45 port. (ethernet)

I've been working with Noobie on AirsoftRetreat to develop a new hopup solution. We've made considerable progress on that, I will release more information as we release it to the public. I made some prototypes and sent them to him for testing by USPS.

Troy tested a few of some old ATX powersupplies and used a jumper to quickly test the output of the powersupply. This website tells you how to jump it. Interesting...
http://www.duxcw.com/faq/ps/ps4.htm

===========================================
Troy and I fabricated the Stepper Power Supply from the various parts we've gathered and purchased. This consisted of:
-Antek Toroid (36VAC/18VAC/12VAC)
-Bridge Rectifier
-22,000 microFarad Cap
-7Amp Breaker.
-Old Pentium II Case
-Blade connectors
-12 Guage Wire (I think)

Troy was hoping to use a cap diode to condition the DC side of the power supply to cause a voltage drop to 36V. On our first test this resulted in a surprising catastrophic explosion of the diode. It was startling, and certainly opened our eyes a bit. We later realized this was because there was no load. Troy surmised to utilize that method would require a lot of resistors that could sap about 100Watts of power - not feasible. We also pondered Voltage Regulators - but they would require too many to properly work.

Forgive if my memory fails me for some of these stats... From the Transformer we were getting 36VAC, and through the Bridge rectifier we were getting 33VDC??. Through the capacitor we were getting 48VDC? This was too high. We measured the voltage in parallel to the capictor with the multimeter. We didn't completely think it through with the transformer because we thought the 36Volts would be DC not AC. Due to the nature of Vrms and the circuit we yielded the high 48VDC. Fortunately the transformer had a couple other power configurations. At 18VAC you get 24VDC through our circuit. So we undid our quick solders and switched over to blade connectors as Troy originally suggested as they are much easier to use. (Yup you were right Troy lol.)

This went off without a hitch, other than the scary part of discharging the huge cap. (as sparks fly) Something about it just feels wrong to drain the capacitor that way... (arcing it with a pair of insulated pliers.)

With the functioning 24VDC power supply we used that to test the connections on the control board. With the board layout properly verified with the multimeter Troy installed the remaining three driver chips to the PCB. I then pulled out an old Athlon computer I had located. We verified the potentiometer settings were correct with the power supply, control board, and multimeter. With the 2Amp rating for the steppers in unipolar mode that yields ~ 0.28VDC on the potentiometer. This stat was found on the specification that came from hobbycnc documentation. They were each set and the cap was drained. We waited several minutes and then refered to:

- http://www.kelinginc.net/KL23H286-20-08B.pdf
- http://www.cnczone.com/forums/showthread.php?t=61976

These were very helpful, and verified our interpretation of keling's documentation. Troy wrote a translation table between the controlboard and stepper documentation which I will take a picture of later. He wired one stepper up to the board after the capicator was less than 0.1Volts. After that, Troy had to leave. Bryan helped me out from then on. We installed Mach3, checked the pulse generation to be a bit shaky for the machine - it seems a bit slow. Sadly, the 750mhz computer has been tweaked for maximum performance already. I have it down to about 16 processes (this is very low.) We were ranging in the 25K to 15K PPS range.

We spent awhile configuring Mach3 attempting to jog the X-axis (the only stepper we had connected.) We figured out how to disable the E-stop break by switching the activelow signal. While this allowed us to green light the machine (make it ready,) we were unable to move the stepper. After a while, we decided to go buy food. Then we stood up and I noticed I hadn't plugged in the Stepper Power supply. LOL. We booted up again, and attempted to jog - no dice. Tired after a long day we got food and headed home.

I hope to figure out the issue by tommorow. I suspect software configuration is at fault.(and hope this too, I don't want to have to resolder the board.) I am certain patience, and persistence will get us through this hurdle.

The prospect of making an axis work is just too exciting! Pictures to come!!

Quick post - tired

Worked on the CNC frame with Troy today, we made some real progress on the Z-axis. Learned a great deal from watching him model. Kept the tasks coming, as we were working efficiently. Troy couldn't start cutting his practice spindle because of the difficulties in cutting a section of the steel off to dimension. We probably will need to borrow Bryan's Chop saw for that task.

I also did some work on some airsoft parts today on the laser cutting machine. Various prototypes are being fabricated for bench comparisons of the different part geometries. (forgive my lack of proper english - i am tired.)

Lastly, I attempted to get the ball rolling on using the CNC machine again. While I was able to generate G-code and cut a part before the shop has changed some of the CNC's control software so we no longer have to remove G28's but now we need to change our post-processor in our CAM software to not use G43 commands. I made a post on cnczone to find a fix about this:

http://cnczone.com/forums/showthread.php?p=663482#post663482

I also did a bit of research on speeds and feeds for plastics here's what I got:
http://www.niagaracutter.com/techinfo/common_mat/polyprop.html
http://www.blurtit.com/q534090.html

I ended up choosing a speed of 766 RPM, with 7.5 IPM (~450 SFPM) with a 3/16 end mill. I'm going by memory for all those, so forgive me if there is a mistake. All that information was derived from the two websites above.

Solidworks at the beach!

Oh yes, I went to the beach with the family this week, and spent some time just getting some old fashioned work done. I treated our deck with an oil, then after the chore sat down for some intimate time with Solidworks!

I sought out to roughly model up the frame for our CNC machine. The purpose for modeling the frame is so we are clear on our dimensions, plans, and specifically to ensure we buy the right ballscrews. I got it roughly halfway done. It was a lot of work switching between specifications looked up online, a slow solidworks computer, and the occasional realization that I would have to make my own assumptions in order to completely model it. This was a large amount of time and effort, here's some screenshots of what I was working on:


Despite all the effort i was only able to roughly map out the X and Y axis. But they move smoothly, and it was made with 75% actual dimensions! This sort of project makes you REALLY appreciate what parametric modeling does for you. I was able to get the design concept done despite a lack of a few dimensions. I turned over the files to Troy to see what he could do with the model. The Z-axis still needs to be done, and we are concerned about its deflection since the head would have to extend out 15" to reach the full working potential of our Y-axis.

Hopefully, we can order the ballscrews soon. I did receive the VXB spindle bearings from ebay last week. We are waiting on VFD esque controller Troy selected for our Treadmill motor, which essentially is a fancy potentiometer that we can control with the computer. I did a rough price estimate of the Bosch extrusions to be around 200$ with end machining - not bad. I imagine it will be a bit more by the time we are done. The mic6 plate will cost a good chunk too - i imagine like 200$. Oh well, so much is the price for extreme goodness!



I also spent some good time learning/grinding through some 3D milling as shown on the part above. Boy there is so much to learn! I feel almost overwhelmed with the magnitude of project potential that seems to consistently stare me in the face. I want to build the world! Alas, I am but one man. That won't keep me from trying though :P

Powersupply preparations

After looking over the components, documentation, and some a gecko document. I've been able to determine that we needed only 4666 micro Farads. This was determined with the following equation:

C = (80,000 * I)/V
C = (80000 * 2.1 Amps) / 36Volts = 4666 mF

Since we are running our steppers in unipolar mode the steppers will draw 2.1 Amps. Bipolar i believe was 2.8 Amps, so we calculated it with 3 Amps and that necessitates a 6,666 mF capacitor. The hobbycnc documentation recommends using a capacitor that is 20% higher than what is requested. From these calculations we see that our capacitor is more than sufficient.

This was not the 27,000 mF that was previously thought. Also from inspection the capacitor Troy purchased is rated for 22,000 mF and 50V. So we are good! We have almost all the components we want for our power supply. We would have built it tonight, but I believe we want some fuses, power switch, and wire. We also need to design and fabricate a power supply box.

I've made some progress on the frame, i'm now toiling with some geometry issues with the frame, and trying to ensure frame stability. The issues are occuring with mounting the THK rails to T-slot bars that will inevitably have to be drilled.

http://buildyourcnc.com/supply1.aspx
http://www.cnczone.com/forums/showthread.php?t=61976
http://www.geckodrive.com/upload/Step_motor_basics.pdf (page 11)
http://www.5bears.com/cnc03.htm

More purchases, and more to come

I've purchased the spindle bearings for Troy's spindle design. He ran some calculations on the angular contact bearings, and also found some ebay bearings that had an ABEC-3 rating. I also purchased a CNC4PC control board that will be used to interface and control the DC motor for the spindle.

Short of 1 Capacitor, I think we have all the major electrical components. I've begun frame design once again starting from scratch, as I've learned some assumptions were not correct that I was working with before. I am particularly concerned with of each axis, as I found in my research that it is difficult to find swarf guarding material of the appropriate size. I want to completely model the frame before making the ballscrew purchase, as we know where to do that. Although, i'm feeling the pinch of time. So i'm thinking I should get that done within the next week.

As I keep track of the fiscal performance of our project. We are in the clear so far, I hope we can stay on track. If anything we are slightly under our projected cost.

In other developments, I reassembled my M4 airsoft rifle, after Troy and I inspected the internals for future projects. You can see some points in the procedure from the pictures. It was actually a lot more complicated to re-assemble than the picture's show. With the anti-reversal latch, and some springs that just didn't want to stay put, I had to come up with some clever ways to hold them in place. Using my Allen wrenches, and some electrical tape, I was able to fix the components in place until I could close the mechbox and remove them. I also had to use the motor's magnets to magnetize my screwdriver, so I could manuever the screws into the pistol grip successfully.


I also setup and started up an old computer, that had problems in the past. I confirmed that the primary harddrive has some bad sectors, and cannot boot to windows. I used a bootable linux OS to take a gander at the drives. The Raid-0 array was fine, all the data on those drives were unscathed. Ironically, it was the single OS hard drive that failed. I was pleased to find no faults in any of the other hardware.

Gathering resources

As I keep my projects moving along I realize that one of the major aspects of projects that can easily be underestimated, is simply the selection and purchase of a given raw material or tool.

Several educated decisions must be made before making a purchase in the hopes of minimizing lost money or time. Today, to keep the ball rolling on one of my airsoft projects I had to make a quick decision about a ball-end mill purchase. As I was modeling my CAM file for the part, I had to choose between a 3/16" diameter or 1/4" diameter. I picked 3/16" because I can interpolate curves with the 3/16" that should be near to similar geometry of the 1/4" ball end mill. A quick run over to Hall tool, and I got the tools. I also purchased a VERY small double sided endmill (1/16"), for some detailed work.


I also received the Toroid Transformer the mail from Antek Inc. It looks like in good condition to me. It is a surprisingly heavy piece of equipment. I need to locate 1 more medium sized capacitor to run in parallel, and we will have all the components for our powersupply. If I can get all these things to Grant, we should be able to fabricate, and finish off the control board. Basically - we will be able to test the brains of the CNC machine. This will let us also test and configure the stepper motors. I'm sure if we can get the board, and the steppers running, the project will quickly accelerate.



There's always a defining moment in a project, where you find out if it is inevitably going to work. I believe we have one coming of those moments coming up with the power supply, control board, and steppers. I mean if we get that done, we essentially need to attach a few more mechanical components, ballscrews, THK rails, and spindle and we have ourselves a CNC machine!

Keeping things ontrack

After a short hiatus due to finals, Troy being gone, and a general state of busyness we started things back up. Oh and I think something or someone is starting to really spice up my life. I hope good things come of that...

CNC Power supply
All that aside, I've been keep things alive with my little airsoft business, Troy seems to have finished the basic shape of the new airsoft part that is under development. We are considering design enhancements, and the serious complications to actually fabricating the part. I just got the ball rolling on the powersupply for the control board thanks to Troy's help. We were able to clear up a few questions I had lingering. From his help I was able to determine:

-The powersupply must have a matching voltage to the control board. In our case we want it at full voltage of 36VDC.
-The current is variable, and will need to draw up to a max of 12 Amps, because each stepper is rated to 2 amps, but according to the information on the hobbycnc kit we need twice the amperage that the stepper motor is rated for. So with 3 steppers that adds up to 12 Amps in unipolar mode.

A quick look on ebay yielded a few subpar powersupply's, and a few way overkill powersupplies that cost 400$. With some searching we found Antek should be able to land us a quality Toroidal transformer for about 55$ + shipping. Troy already bought a bridge rectifier, and capictor. Although the calculations indicate that we will need to run another small capictor in parallel with the large 22,000 mF. This is because we need about 27,000 mF as dictated in http://www.geckodrive.com/upload/Step_motor_basics.pdf on page 11.

=======================

Frame deliberations

After discussing 80-20 extrusion availability and cost we are considering getting some budget extrusions off of ebay. The only problem with this is that it will not be end machined or have any tapped ends. Going with the more expensive Bosch option will give us that, saving us some trouble. I think i'll need to get a price quote from bosch to ensure that ebay is indeed the better option.

The biggest issue I was encountering was mounting the Z-axis to the X-axis similar to 5-bears. After consulting Troy, he came up with a great idea to simply bolt the Z-axis to an intermediate base that serves no function other than to be a stationary mounting base.

The base most likely will be two 45-90 extrusions of full length attached to mic6 plate which will also mount the Z-axis. I'll need to calculate the deformation induced by the weight of the X-Y axis with a 45-45 section modulus to be sure they will be sufficient. If not I'll have to step it up to a stronger section modulus that can prevent the deformation.

Lastly, I still need to find out where to get the T-slot steel stock for mounting the fasteners for each axis.

The good news is after today, we have a real plan for all the major components of the CNC. Where to buy them, how we will integrate them. Now we are down to a few of the details, and the daunting task of coalescing it all together! But oh my, it is so much fun.

Batman would be proud. Progress.

This is my second attempt at making a post, because firefox decided for me to crash. Thanks firefox! Anyways... onto the real stuff.

(Picture of grant owning this PCB)

Today, I went over to Grant's house and we started to build the hobbycnc control board. We put Grant's fancy soldering iron to work on the PCB. For the most part he was doing the soldering, and I was ensuring component placement based on the schematic and instructions from the kit. What was nice, was that the board was clearly and neatly ordered/organized. I did solder a few components just for good measure, and to remind myself how fun it can be. I see it as a miniature TIG welder without the annoying foot pedal.



(I'm soldering on a few parts just to make sure I can still do it; and I can yay!)

If I build another CNC I will seriously consider using this company again. The only two shortcomings that i forsee with this board is the lack of opto-isolation (although troy believes he has a fix for this), and secondly the lack of high voltage so we can't overdrive the stepper motors much. While this board can only go to 36V the Gecko Drivers can go to 80V, although the nice thing about this board is that it is almost all contained on this board.

So we built almost all the board, with exception to some of the logic chips. The reason is you want to test the board for solder bridges and continuity before applying current and voltage that could potentially damage the expensive logic chips. Once you are sure your board is functioning properly with the powersupply connected you can install the logic chips.

Given that we didn't purchase a powersupply yet we could not finish off the board completely. This is because Troy and Grant were going to explore the option of fabricating a powersupply from old parts from a microwave power supply. From the documentation it looks like we need an 18A powersupply; at this point I don't know if it's okay for us to exceed that, although my gut says its fine.

Here's a website with some good information about building or buying a powersupply http://www.solsylva.com/cnc/power_supply.shtml

Keep chugging along

Steppers ordered
While dealing with my Discrete math class (scored 100% on the midterm wooo), and keeping my airsoft business alive (shipping product); I managed to select and order some 425 oz-in stepper motors for all 3 axis on our CNC machine. All together with shipping it was 163.17$, We could have gone with a ~300 oz-in motor for 30$ less, but the price/performance difference was warranted an increase in power. We wanted to be sure we could meet our torque requirement. We are happy with rapid speeds of around 70 IPM, but we are confident with appropriate gearing/microstepping we can hit whatever targets speeds we need. Other than the previous research and calculations that were conducted a few days/weeks ago (with that program I wrote), I did additional research on cnczone. The interesting reads I found were:

http://www.cnczone.com/forums/forumdisplay.php?f=193&order=desc&page=17
http://www.cnczone.com/forums/showthread.php?t=27527&page=2
http://www.cnczone.com/forums/showthread.php?t=80245
http://www.cnczone.com/forums/showthread.php?t=75192&page=2
http://www.designworldonline.com/articles/3807/21/Improving-High-Speed-Performance-of-Hybrid-Stepper-Motors.aspx?utm_source=mcnl&utm_medium=newsletter&utm_content=feature&utm_campaign=MCNEWSLETTER
http://www.homeshopcnc.com/StepperMotorFAQ2.html

Also while inspecting specs on keling's website I needed to convert 2.15N-M to oz-in, a quick google solution was found at:

http://www.unitconversion.org/torque/newton-meters-to-ounce-force-inchs-conversion.html

It looks like our machine will be severaly limited on the Rapid speeds based on the controller board, with a max voltage of 36V. So we can't overdrive the steppers much. They run 6V stock. So we will only be able to run them about 2x their rated voltage even though we could go up to 20x their rated voltage. With the stepper order aside, I continued my frame research for our machine.
-----------------
Frame Research
For awhile we were seriously considering making the whole frame out of epoxy/granite composite. But after eyeing the costs, the difficulty in manufacturing and the time frame we are on, Troy and I decided it would be wise to follow the KISS principle. I had found several instances of aluminum Bosch framing for homebuilt CNC machines. Given the repeated success I had found, I pushed for what we know works, and with ease. Given our constraints on the project Troy, agreed heartily. Although, we both conceded it would be very cool to incorporate some E/G aspects into the project later to enhance rigidity and vibration absorption.

A simple way to do that would be to fill the cavities of the aluminum framing with E/G. Also we also conceded it would be very nice to have a solid head, so we may make that solid later. At the moment I am toiling with fasteners. I measured one of the THK rails we obtained from ebay. They appear to have 7mm holes for SHCS (Socket Head Cap Screws.) and 9mm countersunk holes. A quick google search is not promising for 7MM SHCS.

http://www.roymech.co.uk/Useful_Tables/Screws/cap_screws.htm

Shows some typical metric SHCS sizes. M7 is not on the list. I wonder if they are specialty screws for the rails, or if they simply use M6 screws.

In my research I began to learn that these so called aluminum frames, are sometimes nicknamed "80-20" extrusions. Which I guess is some sort of industry standard. Apparently there is even a whole section on cnczone dedicated to 80-20 frames. (i'll have to read into it more before making final design decisions.)

From an inspection of Bosch's website and manuals it looks like a 45x45H extrusion section should meet our demands for the X/Y tables. I am a little concerned because milling flat that extrusion will be a hastle on the bridgeport mill that hasn't been opened up yet at our shop. Not to mention we don't even know if the bridgeport's ways are true. Any error in that machine will be amplified in our own base if they are off. And from my research it is not uncommon for these extrusions to have about .008" of variability across a single piece. I also read some individuals using T-slot inserts that are premachined and have SHCS holes in it. I hope i can find more on this.

Some websites concerning 80-20 framing:
80-20 surplus
80-20-T-Slot-Aluminum-Extrusion-45-S-45-4545-
Bosch 3D models
Bosch Website
http://www.3dpublisher.net/SWDownloads1/2044316659-857082/Machining.PDF

I know I will be ordering some Mic6 precision ground plate for bolting some of these frame parts together, just don't know the physical dimensions yet. So that's on hold. I want to model the whole thing in solidworks first.

So to review:
I need to:

• M7 screws- do they exist for the THK rails?
• Precision ground t-slot rails for 80-20 t-slots to bolt the THK rails to - do they exist/where?
• 80-20 End machining options at bosch are confusing, figure it out!
  
• Model it!
  

The truth about building a CNC machine
Gosh everything about this project is Read, Read, Read, process, learn, discover how very little you actually know, rinse and repeat. And somewhere in there you feel confident enough that you aren't going to make a disastorously horrible mistake, and that it is about time to learn by doing.

Progress, but slow

I'm getting this lingering feeling that all the projects I'm doing are getting spread too thin. There is considerable progress when you look at the big picture, but I feel they are getting off track. This shotgun approach to picking tasks I don't think works for the longterm. I may need to review my project goals, and evaluate what would be the most worthwhile use of my time. Despite this I'm still having fun, and doing really cool things.

Like today I started and finished an End-mill box. I'm becoming more proficient at developing and converting designs to be used with the Epilogue laser cutter. Here are two things I made today:


An endmill box and a Metric/English Ruler. I accounted for the laser's thickness to be .004" this made a very snug fit. So snug in fact that when i first assembled it - it took me a full 10 minutes to pry it apart to put the ribs in. I'm going to have to come up with a solution for that. Possibly a bit of simple sanding. I'll have to make a second box as I apparently have about twice as many endmills as depicted.

The ruler, didn't come out that great because the driver interpreted some of the lines that I intended to be engraved, as cutting lines. So the ruler is fairly serrated as the image shows. I'll have to make more later, but hey at least its decently accurate and useful!

Airsoft Business on its feet

Airsoft Business
I visited the USPS post office today and figured out the shipping details for the airsoft products that I've developed. After figuring that, and some tests with the hopup arms that I developed; I released it to the public. After a few sales, I quickly discovered why secretary's are useful for this sort of work (it takes a surprisingly large chunk of time and effort.) I now have a newfound respect for them. It is so rewarding to see a product you've developed being distributed to help others with their goals. (Albiet, that is for playing airsoft lol)

CNC Progress
We fairly accurately priced out several of the future components we need. From this assessment the total cost of the CNC will be around 1733$. So split among our team that will be 577$ per person. Not bad.

Pricing the frame was interesting, because we decided to make it almost entirely of a aggregate/resin mix. We will use what is called "play sand" found at your local hardware store for about 5$/50 lbs. We estimated a "log" geometry where it will be formed from a series of legs that are connected together with a log geometry of 4"x4"x35" we overestimated a required volume of about 840 in^3 for the composite frame. With about 20% resin usage that puts us at a required resin volume of 4 gallons. (924 in^3) The cost of resin is about 200$ for that much. If we get lucky and can get away with only 2 gallons which would be ideal because that would insure a good dampening effect from the frame.

I think a good mixing idea would be to mix the resin without hardener in the aggregate mix before adding the hardener, that way we can ensure the resin is fully distributed through the aggregate.

What a wonderful Day

I finished making a batch of airsoft parts that I will be distributing. I had do prototype tests to ensure they fit properly. I had some issues with localized heat in the acrylic which was causing deformation to occur. A few tweaks to the geometry of the part fixed that. I also finished making the "wooden box" except I used what i had available - which was acrylic. I may make some more boxes later out of wood. Here are some pictures.



Some of the airsoft parts i manufactured (in clear) compared to the original stock factory part. I made all of these parts with a 45 watt CO2 Laser.

Wooden box

Not much happened with engineering today. I had discrete mathematics today, came back from class and received a letter from the MECOP program saying that I had been accepted! http://mecop.ous.edu/

I finished modeling a wooden box to cut out of .25" thick wood on the Epilogue laser cutter at the tech shop. It was surprisingly more difficult to model then the rotary table... This is because the geometry of the lid required me to do some math. Also the corners of the boxes required some interesting thought which I had not performed before.

I'm going to have to convert it to a DXF file, or make a drawing file from the model because the Epilogue 45 Watt CO2 laser cutter needs lines defined as hairlines and converting between file types sometimes you lose that vector based geometry in the image.

Reference:
http://www.woodworkingcorner.com/kschest.php

Rotary table calculations

Image from: http://upload.wikimedia.org/wikipedia/commons/archive/2/2c/20080518200048!Terms_involute_gear_engagement.PNG

Rotary Table

For the rotary table we will be making a gear cutter, worm, and worm wheel. I just "figured out" an equation for calculating TPI, and worm gear teeth. Starting with S=r(theta) I derived:

60/TPI = r(2*pi)

Where 60 is the gear ratio of the worm gear to the worm wheel. Referenced below (in the previous post) is what lets you calculate the resolution that will give you on your table. The 'r' in the equation i suspect is the diametrical pitch, or namely the diameter where the force of the gear is being transmitted, not the OD of the gear. Anyways with this equation I can adjust my TPI for the cutter, and worm gear till I find a TPI that matches what the lathe is capable of cutting. Now in my research i did find that 40' was common for this application no the 60' degrees you typically see. So I need to do some more research or simply "test" it out with an ACME cutter that i already have. (I'd prefer to take the simple route)

An example calculation yielded:
8 TPI, would yield a 1.1936 radius worm wheel.

CNC update + rotary table start

I received our first CNC package of THK linear rails, they are about 30" long were used, but in great condition. My only gripe is the wipers on some of the carriages have a tendency to "catch" on the rail a little bit. I simply hand bent it up a marginal bit and it rides smooth as butter. You can see the ground sheen off them. I put electrical tape on the ends of the rails to ensure the carriages don't slide off. Pictures of these rails will come later.

I had done some research on the spindle, and found several examples of folks using treadmill motors to power their mini-cnc's typically in the 2-3 HP range, (DC motor) with an operational range of 0-6750 RPM. I didn't know much about the controller, and Troy instantly thought that was a great idea, because the VFD we were looking at for the 3 Phase 3HP motor he has would cost 300$. Where we found a treadmill on craigslist for 20$. Hopefully we can pick it up tommorow for that price. In any event he found a DC controller for the motor for less than 100$ on ebay on a 'buy it now' auction which puts at a much more cost effective solution for the motor control system.

There was also a discussion about frame materials, cost, rigidity, ease of manufacturing, and ease of transportation. So things like extruded high grade aluminum (6061), welding steel vs. warpage, and granite composite were discussed. No conclusions were drawn up with that except that we want our solution to incorporate all the attributes listed above.

When I met Troy and Bryan at the techshop. They showed me how to do assembly's in SW. This made me tremendously happy because it's like doors are being opened up for my imagination. Since we finished the fly cutter, we are now going to move onto other bigger and better projects, (which involve the use of our previously made fly cutter tehehe.) This time it is a rotary table. So I started working on modeling the rotary table on solidworks. Here is what i've got so far:



One of the problems i'm encountering is I don't know the dimensions for a standard t-slot so i went with an arbitrary depth of 1 inch and 0.25" slots. The beauty of parametric modeling, is I can go back and fix the dimensions later, Yay! I've also been playing with screw placement, clearance issues with mounting bolts and the bolts that hold the rotary table together.

The problem is I'm trying to make use of material that I already have (0.38" thick steel stock.) Which I have plenty of so I'm going to have to carefully play with the dimensions and design internal blocks to bolt everything together since 0.38" steel is not thick enough for me to comfortably drill and tap strong bolts into it. While I could calculate the yield load and fatigue life of bolts that would fit into the stock, I simply am going to use the KISS principle and oversize the bolts, and use internal mounting blocks.

References:
http://www.technologystudent.com/gears1/worm1.htm
http://www.helicron.net/workshop/gearcutting/cutting_gears/
http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.easynet.co.uk/_chrish/worms.htm
http://www.cnczone.com/forums/showthread.php?t=63992

Fly cutter test

The fly cutter was tested today! Admittedly, I still have to use these silly bolts that "bump" into each other because that is all i could find at Lowe's/Home Depot. Apparently it's not wise to make something 1/4-28 NF thread. I did see quite a bit of 10-32 NF though.



I hand ground a HSS-cobalt blank on the cheap Ryobi 6" grinder at the shop. I noticed the wheels were pretty dirty from dust/aluminum. So I located the dresser, and dressed both wheels (they were in bad condition.) From there I found a bucket of water and got to work using cnccookbook.com as a guide. The rounded edge for cutting was the hardest part. I think i took a little too much off so it likes like 10-20 thousands wide, where the guide i read said you should go for 3-6 thousands. Oh well. It worked!

Here is a v-block i used earlier, and i faced one side with the fly cutter in a jiffy, hand feeding around 4ipm at 660 rpm. (High speed i know - but there is no lower gear on that machine.)

CNC update

I have successfully purchased all the linear rails i'll need for the CNC. They all are THK brand, the Z-axis has HSR20 carriage blocks for the moment load. The x and y axis are on SR20 and SR25's. We'll use the SR25's on the X-axis to take the weight of the Y-axis. The lengths for each axis are:

x-axis = 32.25"
y-axis = 29-7/8"
z-axis = 20"

Now these linear rail length's are the total length not the travel length, because the carriages when bolted up to the table mounting plate will be taking something like 8" off the total travel. So a rough guess of our work envelope will be something like:

x-axis = 24"
y-axis = 22"
z-axis = 12"

We now are working on locating screws and purchasing screws. I also purchased http://www.hobbycnc.com/products/hobbycnc-ez-driver-board-kit/ for 64$. We are holding off on the steppers for just a bit to finalize our torque requirements. Troy has been busy on the spindle design. He sucessfully modeled it up in SW, and he is performing FEA calculations on it. While I did find him some angular contact bearings that dimensionally work, and financially work, they did not have specifications on the tolerances. Troy has been working on some equations he can apply to ensure everything falls into our safety factors.



I have been keeping a spreadsheet on expenditures... Oh man it's starting to add up. I alone have purchased 450$ worth of parts specifically for our CNC alone. Troy special ordered some 4340 for his spindle for 50$. He also needs to make a tool post grinder, take a safety milling class, and buy angular contact bearings, and a VFD (300$) all for the spindle. This is going to hurt our pockets. This is really going to start being the "test" on us, we are on a tight budget (our own pocket money no less.) Our wits, our ability to scrounge, our courage, and our vigor are all going to be necessary to get through this project. The last project that i have taken part in that is of this magnitude was the 2008 HPV project. That said back to research!