Hi, first post here I'm about to commence building either a Lead CNC or Workbee 1 metre square size. I have previously built an MPCNC, and a small dremel cnc. If I use the high torque steppers that generally come with the kit, I will need to replace all my electronics, which adds about $500 to the build cost (I'm in Australia), however if I select the lower torque Nema 23's, I can reuse electronics from the MPCNC, or a small Arduino/CNC shield. I have a complete wiring set for these including endstops etc.. Is there a big advantage for the high torque steppers, such that it is worth spending the extra money on a complete new set of electronics? Especially since the MPCNC seems to do OK running with just Nema 17's that have half the torque of the standard Nema 23's My proposed usage is a small amount of aluminium milling, but mostly woodwork including some carving stuff that may take several hours to complete. I am trying to keep costs down as I am a retired pensioner, but I will spend the extra IF there is a significant advantage to the high torque motors. More questions to follow TIA Gary
The 270oz Nema 23s will overpower any v-wheel based machine. I seriously question why people get the high torque stepper for machines like the Mini-Mill. I'm not down talking any of these machines, just being real.
Hi Gary, greetings from over the ditch. What are your Nema 23's rated at? 185 oz-in perhaps? If so, they will do the job I'm sure and they are what I originally intended to use myself. Cheers
It's a question of balance - can the structure of the machine provide the rigidity to make use of the power of the high torque motors? Putting an F1 engine in a family saloon doesn't work. Alex.
Thanks Kevon. Christian, they are the 1.26nm or 178 oz.inch variety. The Nema 17's on my MPCNC are rated at 76 oz.inch and they seem to work well...I wondered if there was some special reason why people wanted the high torque motors. cheers Gary
Besides ego? Even if you intend to reuse your Arduino, the typical drivers included on a shield will still underpower the typical 2.8A 178s. You can easily add standalone drivers to go with your Arduino though which shouldn't run you anywhere near $500.
Little A4988 / DRV8825 drivers are still a far cry from running even the regular motors optimally. You'll still have skipped steps and overheating problems with that setup. Save the money, go for the cheaper motors, but add a BlackBox to your order, you won't regret having decent drivers! Its not $500 (;
The original poster hasn't said anything about using A4988 drivers on his new build or his current machines or even if he had them - what he did say was that he had the electronics to run lower torque Nema23's. We need some clarification on what drivers he does in fact have in his possession.
I think the assumption was made because MPCNC suggests using the DRV8825 with a shield or RAMPS board. It is a fairly lightweight machine so the drivers probably work fine for it. But you are correct. His driver information will help. In my personal experience, DRV8825s will overheat and skip steps with a larger robust system and Nema 23s at 270 oz. That was with a large house fan blowing directly on the heat sinks. After getting rid of those and replacing them with DQ542MAs, I have had no issues. But like I said, my machine probably has a heavier gantry than many other people's which led to my problems with those small low amp 3D printer drivers overheating. Many folks have had good luck with the Xpro boards on smaller machines which use DRV8825s.
Hi, I have a LeadCNC with the high torque motors, and I doubt you need them. I bought them, only because I want my lead CNC to grow and will replace parts with more rigid options. But, those steppers are *powerful* and if you crash your CNC with those babies, you will almost certainly replace some bent or broken parts.
So what you are saying is after installing my new high torque steppers, I should finally get around to hooking up my limit switches. You have inspired me. Thanks for the heads up. I have procrastinated on that for four years now.
