Re: PM-932m CNC Conversion
Steppers / Servos:
I think for the motors for motion, I'll pick closed-loop hybrid steppers like these from Lichuan:
With the AliExpress Sale starting on November 11th, I can get three of these beefy closed loop steppers for just under $600 with shipping.
Toroid Transformers add to the cost, one per stepper driver.
AC servos are also available, but they start at around $200 and the torque ratings are different...
Control Electronics
I will probably go with the Mesa US PCIe Stepper Kit, and run LinuxCNC.
Re: PM-932m CNC Conversion
Also possible alternative for the Z-axis stepper, a closed loop stepper with a brake:
https://www.omc-stepperonline.com/cl...tic-brake.html
Re: PM-932m CNC Conversion
Might choose the Leadshine versions, their documentation seems to be better (it exists):
Leadshine CS-M234120 (without Brake) for the X/Y axis.
Leadshine CS-M234120B (with Brake) for the Z-axis.
Stepper Driver CS-D808
Re: PM-932m CNC Conversion
Ball Screw Kit:
linearmotionbearings2008 on eBay has this kit:
X Y & Z ball screws kit 772mm/397mm/602mm for ENCO RF45 CLONE CNC conversion
If the pictures look familiar, they're from KCJ:
https://www.cnczone.com/forums/rf-45...ml#post1991518
But these are sold with double-ballnuts instead of two separate ball nuts.
2 Attachment(s)
Re: PM-932m CNC Conversion
Playing with the idea of mounting Hiwin QR-series heavy-duty rails on the axises (axii?).
The QR Series uses rollers instead of ball bearings, so they're for super heavy duty motion.
These are the 30mm wide models, with flanged carriages.
I got the idea from CNC4RX7 on YouTube, who's doing something similar with a PM-727.
He has his ballscrew inside the column, I'm thinking of moving the ballscrew forward and filling the column with epoxy granite.
Attachment 430668
Attachment 430670
Re: PM-932m CNC Conversion
Linear Rails
I think I'll go with Hiwin genuine HG series rails, from motionconstrained.com:
Z Axis: 2 x HGH20CAZAC rails with normal blocks, 20mm rails 760mm long. $288
X Axis: 2 x HGH20CAZAC rails with normal blocks, 20mm rails 820mm long. $299
Y Axis: 2 x HGH20CAZAC rails with normal blocks, 20mm rails 520mm long. $245
Total: $832
The rails are longer than the dovetail slots, so I'll have to support the ends for some overtravel.
Re: PM-932m CNC Conversion
Hybrid Closed-Loop Steppers
Prices from Leadshine USA (leadshine.com):
2 x $148: Leadshine CS-M234120 (without Brake) for the X/Y axis.
1 x $208: Leadshine CS-M234120B (with Brake) for the Z-axis.
3 x $129: Stepper Driver CS-D808
So total cost: $891
Re: PM-932m CNC Conversion
Hiwin RG Series Rails
I am also getting quotes for the Hiwin RG Series rails, which use angled rollers instead of ball bearings.
RGH20CA2R520ZAHII: $671
2 x RGH20 rails, Heavy Load, Standard Block, Medium Preload, Precision H, 2 blocks per rail, 520mm long.
RGH20CA2R760ZAHII: $718
2 x RGH20 rails, Heavy Load, Standard Block, Medium Preload, Precision H, 2 blocks per rail, 760mm long.
RGH20CA2R820ZAHII: $741
2 x RGH20 rails, Heavy Load, Standard Block, Medium Preload, Precision H, 2 blocks per rail, 820mm long.
Total: $2282
This quote was from Braas Automation, brassco.com.
What's interesting about these prices is that the rails are cheap - but the bearing blocks are $132 each!
Re: PM-932m CNC Conversion
I'm looking at the TBI Motion store for Ball Screws:
https://www.aliexpress.com/store/1797664
They have some double-nut C3 or C5 grade ballscrews in 2005 series that are interesting:
https://www.aliexpress.com/item/32942915298.html
The manufacturer's page has info and drawings/cad:
https://www.tbimotion.com.tw/en/page...e-catalog.html
https://www.tbimotion.com.tw/en/download/index.html
3 Attachment(s)
Re: PM-932m CNC Conversion
X-Axis Ballscrew
Came up with a simpler mount for the X-axis ballscrew and motor mount, allowing for a full length ball screw and more travel.
The parts are designed based on off-the-shelf components:
- MBA15-F Nema 34 Motor Mount
- FK15-F Fixed End Flanged Bearing Block
- FF15 Floating End Flanged Bearing Block
- MGD-20 Ballnut Mounting Block, modified with 6mm cut off from the bottom and the top.
The only custom parts are the 15mm thick plates on each end of the table which serve as the mounting points for the ballscrew assembly.
The Ballscrew is looking to be a 2005 series (20mm, 5mm lead), with a DFU/OFU double-ball nut.
The saddle will need some minor pocket machining to fit the MGD-20 mounting block, I could probably even bolt it down to my tiny X2-series mill to do that.
Attachment 430798
Attachment 430800
Attachment 430802
Re: PM-932m CNC Conversion
AC Servos
Decided to splurge and go for DMM AC Servos and DYN4 drives:
- 86M-DHT 0.75 kW AC Servo on X
- 86M-DHT 0.75 kW AC Servo on Y
- 86M-DHT 0.75 kW AC Servo with Brake on Z
- 3 x DYN4 AC Servo Drives
Cost: $1643
The DYN4 AC Servo drives have the benefit that they can run directly off of single-phase 110/220V AC, so a DC power supply or an AC toroidal transformer isn't required.
For controlling hardware, I'm going to with the Mesa electronics 7I77 6-Axis Servo control board, and either a PCI/PCIe 5i25 or 6i25 card and LinuxCNC.
5i25-7i77 PCI Kit
6825-7i77 PCIe Kit