Saturday, 6 February 2021

Pulley slotting using Centroid Intercon conversational programming

I got a 5mm pitch timing pulley from some guy on ebay, ready to slide straight on the servo motor to drive the Z axis. That turned out to be a rookie mistake. I agree it appears to be 5mm pitch but it's not compatible with the HTD pulley and belt I got from Bearing Boys. Bollocks. So I got another one, this time from Bearing Boys.

The Z axis pulley is one of those "pilot hole" ones ie has only a 5mm or so pilot hole drilled through the centre, requiring you to drill / bore it out to suit your application. In my case, I need a 14mm bore with a 5mm key. I'll bore the hole in the lathe (manually of course!) and then slot it in The Shiz.

First, the boring work:

Setting up

Drill 12.5mm

Bored out to 14mm. Spot on....

"Snug" fit

Then the key part:

There's no point buggering about in Fusion to create a simple toolpath for the slotting operation. having said that, I'm not up to manually creating myself. Or even if I were, I expect it would take longer and be more fraught than using the Intercon conversational programming feature in the Centroid software. This seems like a good time to get reacquainted with it, having only used it a couple of times, some time ago.

You start out with a blank file and add operations using the forms they present you with. This looked like a good start:

Hmmph. That won't work. Requires some spindle rpm ideally. For that it seems you need to add a "spindle" line like this:

Then the "rectangular pocket" operation:

This is what it created:

; ICN_PATH = C:\intercon\Slot clearing.icn
; --- Header ---
N0001 ; CNC code generated by Intercon v4.50
; Description: Slot clearing
; Programmer: Muzzer
; Date: 05-Feb-2021
  M25 G49 ; Goto Z home, cancel tool length offset 
  G17 G40 ; Setup for XY plane, no cutter comp 
  G21 ; millimeter measurements 
  G80 ; Cancel canned cycles 
  G90 ; absolute positioning 
  G98 ; canned cycle initial point return 
; --- Tool #22 ---
;Tool Diameter =    4.0000  Spindle Speed = 6000
;4mm e/m carbide
  G49 H0 M25 
  G0 X0.0 Y0.0
N0002 T22 M6
  S6000 M3
  G4 P3.00 ; pause for dwell
  G43 D22
; --- Rectangular Pocket ---
N0003 X0.0 Y9.055 Z3.0 H22
  G1 G91 X0.0 Y0.0 Z-3.0 F100.0
  X0.0 Y0.0 Z0.0 F50.0
  X0.0 Y-1.555 Z-0.417 F100.0
  X0.0 Y1.938 Z0.0 F100.0
  X0.0 Y0.312 Z0.0 F50.0
  X-0.625 Y-1.125 Z0.0 F100.0
  G0 G90 X0.0 Y8.0 Z3.0
; --- End of Program ---
N0004 G49 H0 M25
  G40 ; Cutter Comp Off 
  M5 ; Spindle Off 
  M9 ; Coolant Off 
  G80 ; Cancel canned cycles 
  M30 ; End of program 

Looked good to me. What could possibly go wrong etc.

Off we go:

Check the key fits before removing the part. Nice.

Then drill 4mm and tap M5 for an M5 grub screw. First place the hole for the grub screw:

Use the same 4mm end mill to drill the hole:

All done. Slightly shortened (12.5mm, was 19mm) long key way.

Job done, fits together.

All I have to do now is order the correct length timing belt (325mm) to replace the 300mm one The Stupid Fat Bloke ordered. WTF was he thinking about?

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