What’s worked and what’s not about using an AC servo motor (DMM Tech DYN4) on a LinuxCNC CNC retrofitted Precision Matthews PM-25MV milling machine. Many of these questions came from viewers and I hope this summary video will help the next person. I’ve tried to be very factual but mistakes are likely about the cause for problems that I didn’t fully solve. Next video will describe the LinuxCNC DYN4 serial interface.
Table of contents
Notes and transcript
Today I’ll share with you my experience of replacing the stock BLDC motor on a Precision Matthews PM25 milling machine with a servo motor from Dynamic Motor Motion. I’ll describe what worked well and what didn’t, in a question-answer format.
I must acknowledge Stephan and Michael at DMM. They answered what had to seem like an endless stream of questions. Also, Jon Elson at Pico Systems for support with the Universal Stepper Motor Controller.
What are the advantages of the stock BLDC motor?
Why upgrade the BLDC motor?
Why not replace the original drive?
Why a servo motor? Why not a VFD driven induction motor?
Why not a servo motor?
What’s the simplest way to interface the servo motor?
Is there a more featureful way to interface the servo motor?
How about torque control mode?
Why not use the stock v-belt? Aren’t timing belts noisy?
Why use the motor’s encoder? Isn’t a spindle mounted encoder better?
Could I have made a more complicated setup?
Why not use a larger power servo than the original 750W BLDC?
Why select a servo with a brake? Doesn’t the brake harm performance?
Is there electrical noise from the servo drive?
Should the high-voltage electronics be installed into their own enclosure?
Could the DYN4 serial interface be used?
Has surface finish improved?
Are the electronics for a CNC retrofit expensive?
Does the motor run hot?
Why has this video taken so long to complete?
Are the LinuxCNC configuration files available?
Would I do this all again?
There are a few items that I’ll expand on in short follow up videos. Let me know if you have any suggestions. I’d be glad to answer questions here, Instagram, Twitter, blog, or email, whatever works for you.
Thank you for watching. Thank you for listening. Thank you for all the love.