Sam, if you get slippage on the 20t you are overtaxing your hardware, and I don't mean the 20t pulley. Maybe slow down the machine? Maybe use a different belt, one more wider and less teeth per inch?

 

Just checking in to see how you're liking the build. Any changes or mods?

 

Great! Good to know, thanks!

 

Very cool. We don't use our "sam Keller Replica" nearly enough. But we still find uses for it occasionally. What kind of speeds are you routing wood at now with the rack and pinion vs the belt before? The problem we see if we go too fast is the belt slips and "looses its place" and ruins the piece.

We added the diode laser as you did as well, but we keep tossing the idea around of adding a plasma cutter to it. I am just not sure if and how the blackbox can handle the plasma cutter. I need to do more research, but I hope to add it to our replica machine at some point...

Impressive Sam!

 

It may be in the video, I haven't watched yet, but what software do you use to send the gcode to machine? Is the openbuilds control software capable?

We currently have a router and laser connected to the blackbox. Do you have to unplug the laser to get the plasma to work?

Thanks!

 

Sam, Im glad to see your back at it. Helps motivate us. Did you do rack and pinion for Z axis too? And I assume you used same stepper motors that you were using with belts? Would you share the name of place in Missouri that you bought rack and pinion?

 

Thanks for the info Sam. You must have known I was about to ask.. 8) So the racks that you ordered; were they the 1/2" , 3/4 or 1" face width . 12, 16, or 20 pitch? I assume you ordered the 12' stock. I dont see any 8'. Did you get gears from there also?
Thanks

 

@Sam Keller, I think we are ready to follow your upgrade to rack and pinion. We are hoping to be able to increase the speed in which we can complete jobs without (what we assume to be) belt slippage. If we try to cut wood at 1/2 the step down of the diameter of the bit, at 70-80IPM or more, we often mess up boards because the machine gets off. I would really like to increase this pretty significantly, and I think/hope the rack and pinion is the answer.

I have called and gotten a price on the r2020 gear rack, but I am trying to make sure I am getting the correct pinion gear to match. The pinion gear must be a 20 pitch to fit that rack correct? I have had a hard time finding a 20p gear pinion. 32p and 48p are abundant. Do you have a link to what you got?

I hope all is well!

thanks!

 

THANKS !!!

@Sam Keller Out of curiosity, how fast do you think you can cut wood now? I know previously you said you are pretty much maintaining about the same speed as before, but were cutting deeper. I am trying to cut 1-1/2" thick pine with whatever diameter bit would be the fastest, but I am only realistically being able to achieve about 70 IPM without worry of messing up the cut. I am stepping down about .2" with a 1/2" bit.

I know I could probably increase my speed if I decrease my step, but I am just trying to figure out what will allow me to finish the job the fastest. I am curious as to how much you think your setup with the r&p could achieve this?

Thanks again!

 

@Sam Keller , did you have to do any modification to connect your power supplies in series? (Isolate grounds?) or, do you just connect the + from one supply to the - of the other and connect the load to the two remaining + and - connections of the two supplies?

Thanks!

 

No worries!
Thanks!
Did you use a diode between the two supplies?

We have made the plunge to the rack and pinion. We just got parts in and beginning to put together yesterday. We got it up and moving, but still need some tweaking.

I wasn’t impressed initially with the ease of stalling the motors on the r and p, but I have reduced the acceleration down quite a bit and it seems to be better. I also had an issue with my blackbox, but @Peter Van Der Walt and everyone at open builds was awesome at helping me diagnose and get a replacement quick! I was very impressed with the customer service!

Long story short: I have the dm556 drivers that I ordered before going with the blackbox. I have another project on the horizon for the blackbox and I want to be able to utilize the higher voltage capabilities of the dm556 driver now that I have gone to rack and pinion. I am hoping doubling the voltage from 24 to 48v will increase the torque of the motors.

I think (at the moment) I have acceleration set to 250mm/sec2 for the x and y axis. This is ALOT slower than it will actually run at, but the torque seems to be so much higher!
My max speeds are around 7500 mm/sec and I can do much higher than this too, but again I am wanting to be able to cut without missing steps more than zip around fast in transition.

Thanks!

 

@Sam Keller
ok, I have it set to 400 and now connected to 48v. Seems to be working fine. At least my rack and pinion addition. While making these changes, I increased the z axis amount of travel. I moved up to a 1040mm lead screw from openbuilds.
I have it all up and running, and everything seemed to work fine (I think). So, I started adding limit switches that I have never added. And obviously had to run wires. Now, when I move the z axis up it sounds ok, but when I move it down it sounds awful. Seems like if it were a “strain” on the motor it would be the opposite. I have checked wiring and can’t find anything obviously wrong. Any ideas what may be causing this?

Thanks!

 

I will check this, but I removed the coupler from the lead screw and run the motor back and forth and it sounds fine in both directions. Wouldn’t this mean the wiring is correct?

thanks!

 

Yes, I could spin it with my fingers. It is difficult to get to one side bc of the location of my limit switches though. However, I have my z axis speed set at 2000mm/min. Acceleration is set to 50. This could be the problem? I have no need to go near that fast, but I set it at that when I had the smaller z axis lead screw and it seemed to work ok. I will lower this speed way down and see what happens. What is your acceleration? What is the height of your z max travel?

thanks!