Servo Driven 4th Axis for CNC Mill

Gallery, Projects and General > Project Logs

<< < (12/39) > >>

awemawson:
Thanks Nigel. There is a pot on the servo card to set the limiting current when stalled and a full 10 volt command input is applied. I have had the manual on file for a few years as this project has been long in gestation :lol:

Andrew

awemawson:
So this morning I've finish off the CAD drawing for the reduction belt drive to the encoder. Now I just need to work out how to hold the stock when machining. (Stock is 200 mm off that long plank of 100 mm x 20 mm aluminium) As I want to cnc mill it at one setting I obviously cannot just grip it in the vice, and there are no convenient lands to put bolt in from underneither that won't finally be cut away. :scratch:

Any suggestions welcome :wave:

Incidentally you can see on the rendering that in an ideal world this would be cut from 110 mm stock, but as I've said before, you work with what you have :med:

Andrew

John Stevenson:

--- Quote from: awemawson on January 17, 2014, 08:44:25 AM ---
Any suggestions welcome :wave:

Andrew

--- End quote ---

Buy a laser, find an old plywood packing case and start off with this.

A bit of PVA and here's one I made earlier :ddb:

Pete W.:

--- Quote from: awemawson on January 17, 2014, 08:44:25 AM ---SNIP
As I want to cnc mill it at one setting I obviously cannot just grip it in the vice, and there are no convenient lands to put bolt in from underneither that won't finally be cut away. :scratch:

Any suggestions welcome :wave:

SNIP

Andrew

--- End quote ---

Hi there, Andrew,

Surely, it's OK to design in features that facilitate manufacture, even if they don't have a function once the component is in use?

How about a boss between the two holes with one or two tapped holes in their underside? Is there room between the pulleys?

Drill and tap the holes as stage #1, then screw the blank to a holder-plate. (Studiously avoiding the terms 'jig' and/or 'fixture'!) :lol: :lol: :lol:
Turn the sandwich over and clamp down via the holder-plate.
Then, stage #2, machine the part according to your drawing (but leave some meat round the tapped holes).

Agreed, this would require two sessions of machining, but .......

awemawson:
OK John, I KNOW I made a masking tape mock up, but a plywood mount is going too far :lol:

Peter, Yes I'm going to have to make some form of jig to hold it and do it in two sessions. I did try tentatively using a longer (*) piece of stock clamped with four hold downs on a sacrificial piece of contiboard. Needs the clearance for the 22 mm profiling cutter to pass round the ends. I put double sided tape between the contiboard and the aluminium to try and reduce vibrations on the finishing cuts, and reduced the through bores by 0.5 mm to leave a solid base to hold things in place. However it let go :bugeye:

I'd already reduced the feed to 50% of programmed rate and had my hand on the E Stop button so it wasn't too dramatic, but that length of aluminium won't now be the finished item :(

However as I'd drilled the holes to mount on the Servo motor and the holes to mount the encoder at least I was able to use it as proof that I'd got my hole locations correct :ddb:

I'm being dragged to a nieces wedding in Bath this weekend so progress will be delayed

(*) I've not yet found how to define 'keep out' areas in Featurecam so I need a fair space between the work and the clamps.

Andrew

Navigation

 Message Index

Go to full version