Newbee and his new machine

[djbillyd007]

I recently finished home made 24" x 24" machine. I used 1" thompson shafts and bearings on all axis held together with an MDF frame. I used 1/2-10 Acme thread for lead screws. I have one of the cheap TB6560 China boards with 175in/oz motors using a 24V supply. I am using Kcam software. It is working great. I have cut /carved wood, plastic, and aluminum. The problem I am having is I can get no more than 12 ipm no matter what I have tried. The first thing I intend to do is replace the 1/2 lead screw with 3/4-6. 1/2 is way to flimsy (should have known better). That is on the way. My plan was to next upgrade motors to start with. I am on a very limited budget here. I would like to stay with nema 23 mounts as I already have them made. I am happy with the machine as is. I am just looking for the most speed I can get with what I have. Anyone have suggestions of a larger motor that might work with this board. Or maybe something else I should be looking at. Right now I am looking at some Nema 23 288oz. motors. not sure how much benefit I will get from them.

[acondit]

I don't know what the voltage limit is on your TB6560 board, but higher volts usually equals higher speed. So, if your TB6560 will take it, you might see what happens with a 35v or 48v supply. Then consider upgrading your motors.

Alan

[djbillyd007]

The datasheet says that the driver is rated for up to 36V but from what I have read around the forums they won't handle it. of course if I had read more on the forum before hand I may have a different driver setup. I may try to put together a power supply and give it a shot. worse case I let out a little smoke. Thanks for the input.

[louieatienza]

I have 1/2"-8, 8 start ACME screws on my machine, 425 in-oz steppers, 24v power supply, and have no problems spinning them at 300rpm+. Like the others said, having a higher voltage power supply, coupled with larger steppers, may help.

The thing with ACME screws and DIY bearing blocks is that you have to get the ACME screw as straight as possible, and make sure the bearings all line up, as well as your leadnut. If your bearing blocks are off parallel even a tiny bit it will bend the ACMR screw. If you get a multi-lead screw (coupled with a bigger motor), you will get a vast improvement in speed. But even the 3/4"-6 should give you a marked improvement.

[djbillyd007]

Originally Posted by louieatienza I have 1/2"-8, 8 start ACME screws on my machine, 425 in-oz steppers, 24v power supply, and have no problems spinning them at 300rpm+. Like the others said, having a higher voltage power supply, coupled with larger steppers, may help. The thing with ACME screws and DIY bearing blocks is that you have to get the ACME screw as straight as possible, and make sure the bearings all line up, as well as your leadnut. If your bearing blocks are off parallel even a tiny bit it will bend the ACMR screw. If you get a multi-lead screw (coupled with a bigger motor), you will get a vast improvement in speed. But even the 3/4"-6 should give you a marked improvement.

The linear bearings and slides are very true. The 1/2 ACME however is not a true as I would have hoped. As far as mechanical binding I can easily rotate everything with minimal hand pressure on the couplings. You have given me hope on the motors providing an improvement. I noticed today if I apply minimal hand pressure on the coupling when machine is running I can easily stall it. I'm probably right on the edge with these motors. Anyone have a cheap source for steppers? I know I can look it up. Hoping to find someone with a similur setup that may have a lead from what they are using.

[louieatienza]

Originally Posted by djbillyd007 The linear bearings and slides are very true. The 1/2 ACME however is not a true as I would have hoped. As far as mechanical binding I can easily rotate everything with minimal hand pressure on the couplings. You have given me hope on the motors providing an improvement. I noticed today if I apply minimal hand pressure on the coupling when machine is running I can easily stall it. I'm probably right on the edge with these motors. Anyone have a cheap source for steppers? I know I can look it up. Hoping to find someone with a similur setup that may have a lead from what they are using.

I could lean on my gantry, and it will push me instead of stalling. And I weigh 220 pounds! I've snapped 1/4" bits clean off the collet by running into a fixture. I bet if you ran the machine at 2ipm you'd havev a tougher time stalling it! There's always good deals on eBay...

[jkarisny]

Originally Posted by acondit I don't know what the voltage limit is on your TB6560 board, but higher volts usually equals higher speed. So, if your TB6560 will take it, you might see what happens with a 35v or 48v supply. Then consider upgrading your motors. Alan

Originally Posted by djbillyd007 The datasheet says that the driver is rated for up to 36V but from what I have read around the forums they won't handle it. of course if I had read more on the forum before hand I may have a different driver setup. I may try to put together a power supply and give it a shot. worse case I let out a little smoke. Thanks for the input.

I too have the TB6560 driver, but I'm only running a 12v power supply with very small steppers. I wish they were faster, but I will wait to step up the power until I build my next machine.

[djbillyd007]

Originally Posted by louieatienza I could lean on my gantry, and it will push me instead of stalling. And I weigh 220 pounds! I've snapped 1/4" bits clean off the collet by running into a fixture. I bet if you ran the machine at 2ipm you'd havev a tougher time stalling it! There's always good deals on eBay...

Thats whats odd, my gantry will do the same thing. However, If I grab the screw or coupling very little pressure will stop it. I build and maintain machines for a living and understand force being muliplied through the screw but I was surprised how much. This also concerned me a bit in thinking of going from 10 threads per inch to 6.

[djbillyd007]

Just a quick update. I got the 3/4 - 6 acme thread installed, cleaned, oiled and checked alignment. I am now getting solid 20 ipm. I am running at 1/8 steps. I tried at 1/2 steps but it seamed to lose steps. Best I can figure the motor is losing torque at about 170rpm. I have been looking at nema 23 torque curves online. I think the next step will be better quality motors. I was suprised to find the torque drop off was so steep on these cheap motors. I am already in the process of building a 32v power supply. Not sure if the board will handle it. I knew going in I was getting cheap electronics for this thing. I guess I should be happy it is running so solid even if it's a little slow. I am never satisfied with equipment. always trying for stronger faster

[Frederic Gagnon]

I have built a 24x48" machine using 1/2-8 lead screws. All my speed/lost steps problems disppeared when I replaced the crappy TB6560 with a Gecko 540. I can do 45ipm without any problems. I have a 24v power supply but consider upgrading to 48v to increase speed.

[djbillyd007]

Originally Posted by Frederic Gagnon I have built a 24x48" machine using 1/2-8 lead screws. All my speed/lost steps problems disppeared when I replaced the crappy TB6560 with a Gecko 540. I can do 45ipm without any problems. I have a 24v power supply but consider upgrading to 48v to increase speed.

I would love to upgrade and have been looking at the Gecko 540. Right now funding is just not there. What size motors are u using?

[Frederic Gagnon]

Right now, I'm using 425oz.in (7.2v/3A) bipolar motors on X & Y. My Z axis is 170oz.in. My first setup was 170 oz.in on all axis but had a lot of stalling, but I was still using the TB6560. I upgraded x & y to the 425s but still some lost steps occured... Only then did I upgrade the controller and all was well, even with the Z axis.

There are some threads here explaining how the TB6560 chinese board design is flawed. Some have found ways to fix it but I'm no electronics guru, so I passed.

Before spending money on new motors, I would definitely consider upgrading your driver. There are some cheaper options than the G540 if you are tight on budget, although this is the one I would recommend.