Dynapath Delta 20 controls - Retrofit or leave alone?

[JimDawson]

What was so bad about Mach3 that you needed to roll your own?

Per customer request I installed Mach3 on a commercial router as part of a general controls upgrade. The machine ran fine at lower speeds, but at the production speeds they wanted to run, it just couldn't keep up. Accuracy was not good, missing steps, etc. I even tried installing a Galil Motion Controller that Mach3 was running, the results were better, but still not adequate. So I just sat down and cranked out a CNC program in about 3 weeks, it wasn't pretty but it worked and solved my immediate problem. Rather than the PC program doing the trajectory planning as Mach3 does, I let the Galil controller do the heavy lifting. That is what it was designed to do and it does it very well.

Are you close to releasing it?

The Win7-10 version is in beta release right now. And the best part; it is absolutely free. Runs steppers, closed loop steppers, and servos. Also runs tool changers, has full spindle control, and PLC functions. The downside is that it will only work with Galil Motion Control products.

 

[Boswell]

Mach3 has it's limitations and as Jim's message implies, it was not designed for commercial use. Having said that, there are thousands (probably a lot more) of people using MACH3 with little or no issues. Don't try to push production speeds, Use a high quality motion controller and a decent computer you can get very good results. If you want a high speed (time=money) system or a system that will NEVER do something weird then possibly Mach3 or any hobby level system is not the right choice. Of course if you have the skills and inclination to write a better system than MACH3 then that is Awsome !.

 

[TomS]

Mach3 has it's limitations and as Jim's message implies, it was not designed for commercial use. Having said that, there are thousands (probably a lot more) of people using MACH3 with little or no issues. Don't try to push production speeds, Use a high quality motion controller and a decent computer you can get very good results. If you want a high speed (time=money) system or a system that will NEVER do something weird then possibly Mach3 or any hobby level system is not the right choice. Of course if you have the skills and inclination to write a better system than MACH3 then that is Awsome !.

Currently I'm using a cheapo import USB BoB with a UC-100 motion controller. I am getting ready to order a PMDX-126 BoB, a PMDX-107 spindle control and a Warp9 ESS. Can you explain a bit further about your statement above that reads, "Use a high quality motion controller and a decent computer you can get very good results." Are you saying accuracy and surface finishes are better, or am I reading too much into this? What are the expected improvements, if any, I can expect to see?

Tom S.

 

[JimDawson]

Tom, I'm going to jump in here with an opinion. Not really going to answer your question. There are a lot of devices out there that the vendor is calling a ''motion controller''. In most cases they are not. A motion controller does it's own trajectory planning/execution, most of the devices available require an external device, such as Mach3 on a PC, to do the trajectory planning/execution. Most of these devices could be considered a signal conditioner at best.

A simple example: You tell the motion controller the X Y coordinates of the table/tool move and the motion controller figures out how to accomplish that task, and applies the proper speed, acceleration, and axis coordination based on the setup parameters.

 

[TomS]

Tom, I'm going to jump in here with an opinion. Not really going to answer your question. There are a lot of devices out there that the vendor is calling a ''motion controller''. In most cases they are not. A motion controller does it's own trajectory planning/execution, most of the devices available require an external device, such as Mach3 on a PC, to do the trajectory planning/execution. Most of these devices could be considered a signal conditioner at best.

A simple example: You tell the motion controller the X Y coordinates of the table/tool move and the motion controller figures out how to accomplish that task, and applies the proper speed, acceleration, and axis coordination based on the setup parameters.

Jim - thanks for your input. I respect your opinion and comments because they are usually spot on. The UC100 literature says the device does it's own trajectory planning and execution but my primary reason for going with the PMDX products and ESS is to reduce/eliminate faults associated with the USB equipment. Jbolt and I had similar electronic equipment with likewise similar USB faults. He has indicated once changing to the PMDX BoB and ESS he hasn't had any faults. I wasn't clear on what Boswell meant in his above post and wanted to hear if there are other features and or improvements that I can expect with the new electronics.

Tom S.

 

[JimDawson]

Jim - thanks for your input. I respect your opinion and comments because they are usually spot on. The UC100 literature says the device does it's own trajectory planning and execution but my primary reason for going with the PMDX products and ESS is to reduce/eliminate faults associated with the USB equipment. Jbolt and I had similar electronic equipment with likewise similar USB faults. He has indicated once changing to the PMDX BoB and ESS he hasn't had any faults. I wasn't clear on what Boswell meant in his above post and wanted to hear if there are other features and or improvements that I can expect with the new electronics.

Tom S.

You can't argue with success.

 

[Boswell]

I don't have a formal definition of what a high quality motion controller is and I replaced the chinese motion controller that was installed on my Mill with the smoothstepper Ethernet and the PDMX-126 with the PDMX 126. I my mind, I put these in the "quality" motion controler bucket. My criteria being that they have a good online reputation by users, they have extensive English instructions, the companies that make them are available and have a public presence (accountability). BTW, I not dispute what Jim says about the definition of a motion controller and the smooth stepper might not be truly a motion controller. but whatever you want to call it, the combination of Mach3 on Windows 10 with the Smoothstepper Ethernet board and the PDMX duo is working very well for me and features that were NOT working with the previous chinese motion controller such as backlash compensation and probe inputs are working. I never had a noticeable problem with accuracy before upgrading or after but I am sure I am not pushing my machine anywhere close to the limits. Time is something I seem to have plenty of. Knowledge of CNC and Machining in general is where my learning curve is the steepest.

 

[TomS]

I don't have a formal definition of what a high quality motion controller is and I replaced the chinese motion controller that was installed on my Mill with the smoothstepper Ethernet and the PDMX-126 with the PDMX 126. I my mind, I put these in the "quality" motion controler bucket. My criteria being that they have a good online reputation by users, they have extensive English instructions, the companies that make them are available and have a public presence (accountability). BTW, I not dispute what Jim says about the definition of a motion controller and the smooth stepper might not be truly a motion controller. but whatever you want to call it, the combination of Mach3 on Windows 10 with the Smoothstepper Ethernet board and the PDMX duo is working very well for me and features that were NOT working with the previous chinese motion controller such as backlash compensation and probe inputs are working. I never had a noticeable problem with accuracy before upgrading or after but I am sure I am not pushing my machine anywhere close to the limits. Time is something I seem to have plenty of. Knowledge of CNC and Machining in general is where my learning curve is the steepest.

Thanks for clarifying this for me. I've been chasing backlash issues for quite some time and made some mechanical corrections. No matter what I do I still have some backlash. I was hoping that it may be electronic based. Tried backlash compensation and it didn't work well with my current BoB. Maybe the PMDX board will cure this ailment like it did for you.

Tom S.

 

[strantor]

I've had very little time to play with the new mill. I do some research on my bathroom breaks, a few times I got to fire it up for a few minutes in the evening. Haven't gotten around to cutting anything with it. Figured out how to run the programs that are already in it, but not how to write my own... I'll figure it out some day soon.

I say all that to soften the blow of the idiot hammer. Until I crawled under it last night and looked, I thought this thing had glass scales on it. It doesn't. I thought that born & bred CNC machines all used glass scales for position feedback. Apparently not.

When I realized it was calculating position based on servo encoder, I decided to test backlash. Man, it's pretty bad. I go one direction and then reverse, it shows position change of .010" before my dial indicator notices. Is that normal for a ball screw machine? It seems to me if it used glass scales it wouldn't matter, but as is I could never make a part with any precision. Do I need to replace ball screws or what? I read that the Delta 20 has backlash compensation hidden away somewhere; I'll try to find it and see if I can make an improvement.

 

[JimDawson]

I say all that to soften the blow of the idiot hammer. Until I crawled under it last night and looked, I thought this thing had glass scales on it. It doesn't. I thought that born & bred CNC machines all used glass scales for position feedback. Apparently not.

Very few have scales on the table. The very high end machines do, but most just have encoders on the leadscrew/motor. Not the best system IMHO.

When I realized it was calculating position based on servo encoder, I decided to test backlash. Man, it's pretty bad. I go one direction and then reverse, it shows position change of .010" before my dial indicator notices. Is that normal for a ball screw machine? It seems to me if it used glass scales it wouldn't matter, but as is I could never make a part with any precision. Do I need to replace ball screws or what? I read that the Delta 20 has backlash compensation hidden away somewhere; I'll try to find it and see if I can make an improvement.

I would expect the backlash to be <0.001 on a good, properly adjusted, ball screw. Ideally set to zero backlash by preloading the ball nuts. Backlash comp is a fallacy IMHO. Software can't fix mechanical problems. It can help, but it's a bandaid. Hopefully that machine has double ball nuts and it can be properly adjusted.