Finally!
My CNC gantry router is finally ready to start making stuff! I'm sure I'll still do a lot of tweaking as I go along, but tomorrow I'll actually be able to start making things.
First order of business will be to go back to Atlantic Carbide to talk to their Onsrud rep, who apparently is only there between 6 am and 2 pm. I need to find out what the best bit for cutting masonite hardboard, which I plan to use in my first project: a business card dispenser. I've already done the CAD modeling and part layout; now all I need to do is to write the g-code. I should have a prototype to show off tomorrow!
Tuesday, November 30, 2010
I had to go and brag about it
So what happens when you go and say that something will be finished on a certain day? Murphy shows his ugly head.
Damn you, Murphy.
See, everything was ready. I had bought an extension hose for the shop vac, and onsrud cutters for the router. I had even done testing! Apparently, I hadn't done enough. Here's what happened:
I got the new motor wired up to one of my cables, poped it on the y axis (it had a longer drive shaft than my other motors, so it fit better there), connected everything, and loaded up the config wizard to make sure my settings were right. X and y axises still worked fine (so the new motor was good), but when I tried to test the z axis, nothing happened. I called someone over to listen to the motor while I tried to drive it, and apparently it would make a faint humming noise, but that was it. I disconnected it from the z axis lead screw, and it still didn't move. Out came the multi-meter. The cable was good. The port on the electronics box was good. I tested the motor on a different stepper driver board and it worked just fine, so it wasn't the motor. This leaves (as far as I know) only one thing that could be failing to work: the z axis stepper driver board.
Some good news: The guy who built the electronics is going to be here soon, he should be able to accurately diagnose the problem. With any luck, it's something silly I didn't know about, and he'll fix it. Also, I have an extra driver board that only needs very minor repairs to be fully functional, so even if the current z axis board is busted, we've got a replacement; no waiting for shipping.
Wish me luck!
Damn you, Murphy.
See, everything was ready. I had bought an extension hose for the shop vac, and onsrud cutters for the router. I had even done testing! Apparently, I hadn't done enough. Here's what happened:
I got the new motor wired up to one of my cables, poped it on the y axis (it had a longer drive shaft than my other motors, so it fit better there), connected everything, and loaded up the config wizard to make sure my settings were right. X and y axises still worked fine (so the new motor was good), but when I tried to test the z axis, nothing happened. I called someone over to listen to the motor while I tried to drive it, and apparently it would make a faint humming noise, but that was it. I disconnected it from the z axis lead screw, and it still didn't move. Out came the multi-meter. The cable was good. The port on the electronics box was good. I tested the motor on a different stepper driver board and it worked just fine, so it wasn't the motor. This leaves (as far as I know) only one thing that could be failing to work: the z axis stepper driver board.
Some good news: The guy who built the electronics is going to be here soon, he should be able to accurately diagnose the problem. With any luck, it's something silly I didn't know about, and he'll fix it. Also, I have an extra driver board that only needs very minor repairs to be fully functional, so even if the current z axis board is busted, we've got a replacement; no waiting for shipping.
Wish me luck!
Today it will be COMPLETE!!
The replacement motor has just arrived! After I finish this post I'm off to buy some Onsrud cutters for the router and an extension hose for the shop vac, I'll slap the new motor on the z axis, and I'll be OFF AND MILLING!!!
It's about damn time.
Over the weekend I did some testing and tuning using only the x and y axises and a sharpie mounted in the router.
As you can see, with the first run (at the bottom), it started off pretty good, but as it progressed the x axis kept slipping. The problem was that since the set screw in the drive sprocket was so small (#8, no head), I couldn't really torque it down tight enough without stripping the socket and/or allen wrench. Thankfully my friend Calvin was around, and offered me a couple socket-headed screws that took a much larger allen wrench, allowing me to apply plenty of torque. While the larger heads did rub the chain, a little quick grinding with my dremel took care of that. As you can see, the final test showed no slippage at all.
Another mod I implemented at the suggestion of others was the addition of two brackets to help support the x axis drive shafts:
We had noticed that when the drive chains were tightened, it would cause the 1/4" drive shafts to flex. To counteract this, Jeff designed and milled out several pieces of MDF to hold an additional bearing for each drive shaft. This way, the shaft would be supported on either side of the drive sprocket, taking most of the lateral tension off the sprocket. They work great.
Off to finish the machine!
It's about damn time.
Over the weekend I did some testing and tuning using only the x and y axises and a sharpie mounted in the router.
As you can see, with the first run (at the bottom), it started off pretty good, but as it progressed the x axis kept slipping. The problem was that since the set screw in the drive sprocket was so small (#8, no head), I couldn't really torque it down tight enough without stripping the socket and/or allen wrench. Thankfully my friend Calvin was around, and offered me a couple socket-headed screws that took a much larger allen wrench, allowing me to apply plenty of torque. While the larger heads did rub the chain, a little quick grinding with my dremel took care of that. As you can see, the final test showed no slippage at all.
Another mod I implemented at the suggestion of others was the addition of two brackets to help support the x axis drive shafts:
We had noticed that when the drive chains were tightened, it would cause the 1/4" drive shafts to flex. To counteract this, Jeff designed and milled out several pieces of MDF to hold an additional bearing for each drive shaft. This way, the shaft would be supported on either side of the drive sprocket, taking most of the lateral tension off the sprocket. They work great.
Off to finish the machine!
Wednesday, November 17, 2010
Setbacks and opportunities
In a response to an earlier post of mine where I had stated that the CNC machine was 'almost done', a friend of mine said "Great! 90% down, only 90% to go!"
This comment is becoming more prophetic than I'd like.
The machine has been capable of movement for a few days now, but the x axis has been troublesome. Even though it's being driven by a beefy NEMA34 motor that should be capable of over 600 oz-in of torque, I've been able to stop it with just a couple fingers. After sleeping on the problem Monday night, I decided to check the documentation of the motors and the driver boards, and discovered that the boards can only supply 4.3A of current, while the motor wants 5.5A. After consulting with some of my friends at the Asylum and some testing, we've decided that the best course of action is to order another smaller NEMA23 motor like the ones currently driving the Y and Z axises, which we know the driver boards can handle.
Some good news is that I had an interview with Because We Can for their internship position that went very well. However, I wouldn't be available until June, and they said that because of their size they can't reliably plan that far ahead. Still, I'm pretty optimistic about the opportunity, and will be staying in touch with them.
This comment is becoming more prophetic than I'd like.
The machine has been capable of movement for a few days now, but the x axis has been troublesome. Even though it's being driven by a beefy NEMA34 motor that should be capable of over 600 oz-in of torque, I've been able to stop it with just a couple fingers. After sleeping on the problem Monday night, I decided to check the documentation of the motors and the driver boards, and discovered that the boards can only supply 4.3A of current, while the motor wants 5.5A. After consulting with some of my friends at the Asylum and some testing, we've decided that the best course of action is to order another smaller NEMA23 motor like the ones currently driving the Y and Z axises, which we know the driver boards can handle.
Some good news is that I had an interview with Because We Can for their internship position that went very well. However, I wouldn't be available until June, and they said that because of their size they can't reliably plan that far ahead. Still, I'm pretty optimistic about the opportunity, and will be staying in touch with them.
Monday, November 15, 2010
Completion is imminent!
So close now!
The mechanics are all done, and the electronics are functional. All that's left is to finish up the wiring and software configuration, which I should be able to knock out today. After that's finished I'll do some test "cuts" using a sharpie in the router to make sure it's moving like it should, and then I'll start milling!
Other than some replacement parts and a few additional ones for the gantry, the first thing I plan on making is a toy I've been working on I'm calling the launcher. The original idea was a snow ball launcher, but then I realized that it could be used to launch pretty much anything than could fit down the barrel, so I made sure it could at least fit a tennis ball. It'll be large, unwieldy, and completely impractical, but it's a great example how a large CNC mill can be used to make things other than furniture and signage.
The mechanics are all done, and the electronics are functional. All that's left is to finish up the wiring and software configuration, which I should be able to knock out today. After that's finished I'll do some test "cuts" using a sharpie in the router to make sure it's moving like it should, and then I'll start milling!
Other than some replacement parts and a few additional ones for the gantry, the first thing I plan on making is a toy I've been working on I'm calling the launcher. The original idea was a snow ball launcher, but then I realized that it could be used to launch pretty much anything than could fit down the barrel, so I made sure it could at least fit a tennis ball. It'll be large, unwieldy, and completely impractical, but it's a great example how a large CNC mill can be used to make things other than furniture and signage.
Wednesday, November 3, 2010
Getting Close Now!
It's starting to look like a CNC!
As you can see, the machine is coming along nicely. I've attached the rails on the z and y gantries, which has allowed me to put all the main assemblies together. Jeff, one of the guys here at the Asylum, wanted to paint the torsion box with a stainless-steel paint, so it's all nice and shiny now. The next big steps will be to fasten the top to the torsion box (it's upside down now), and put it on top of the table structure. Once that's done, I can install the long x-axis rails and chains. Almost there!
As you can see, the machine is coming along nicely. I've attached the rails on the z and y gantries, which has allowed me to put all the main assemblies together. Jeff, one of the guys here at the Asylum, wanted to paint the torsion box with a stainless-steel paint, so it's all nice and shiny now. The next big steps will be to fasten the top to the torsion box (it's upside down now), and put it on top of the table structure. Once that's done, I can install the long x-axis rails and chains. Almost there!
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