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
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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.
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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$, while we could make it lower cost, we are looking to make a rigid, precise, modular system that will allow upgrades in the future. As such, the design is oriented for the future the cost accordingly goes up. It also means - I will likely have to make the spindle. Eeep. Thankfully our school has excellent machines for the task.
My goal for our team is to get all the electrical components, flawlessly interfaced with the computer and Mach3 before I head down for school. While we have the 3 steppers interfaced, there still is the skipped steps to address, and tuning up a computer for the CNC; there still remains the task of getting a powersupply working for the treadmill motor, hooking it up to the CNC4PC board, and interfacing that board with Mach3. A big, but reasonable goal. Even if it doesn't work out this week, we are all patient, and want to do this well and correctly.
Engineer on!
A preliminary assesment puts the frame cost around 500$, 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!
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