Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet

[Snapper]

Just a note on the 8mm drill bit these spindles really don't like spinning slow enough and the framework isn't strong enough you will dull bits faster than you can blink. 6.5mm is ok for predrilling.

[JOGARA]

Still having problems with accuracy.

I have my custom vice jaws that hold my case parts. I use the probe to touch off for origin.
I then run a small test cut to double check and it is usually 0.1-0.2mm out in Y.
I then test again and looks fine.

Remove part from vice and replace with same part, and for some reason the X is now out by quite a bit. 0.3-0.5mm from the looks of it.
I know the vice clamping down on the part does make it bend slightly. But I am only going finger tight to reduce this.

Any ideas?

Literally the last operation on the part to chamfer it. I would do it by hand if I could but I also have to drill holes for bolt heads.

[Snapper]

Still having problems with accuracy.

I have my custom vice jaws that hold my case parts. I use the probe to touch off for origin.
I then run a small test cut to double check and it is usually 0.1-0.2mm out in Y.
I then test again and looks fine.

Remove part from vice and replace with same part, and for some reason the X is now out by quite a bit. 0.3-0.5mm from the looks of it.
I know the vice clamping down on the part does make it bend slightly. But I am only going finger tight to reduce this.

Any ideas?

Literally the last operation on the part to chamfer it. I would do it by hand if I could but I also have to drill holes for bolt heads.

You're using a drill vice, you're never going to get repeatability out of it, 0.1-0.3 isn't bad considering. They don't close evenly, the jaws don't shut parallel, they push the work up when they close and as you've mentioned because your part is thin it's susceptible to bending.

As I mentioned before, a jig plate would be a far more suitable fixture for the 2nd setup. Once made it would be much quicker to set up and a lot more accurate and repeatable.

[JOGARA]

You're using a drill vice, you're never going to get repeatability out of it, 0.1-0.3 isn't bad considering. They don't close evenly, the jaws don't shut parallel, they push the work up when they close and as you've mentioned because your part is thin it's susceptible to bending.

As I mentioned before, a jig plate would be a far more suitable fixture for the 2nd setup. Once made it would be much quicker to set up and a lot more accurate and repeatable.

No idea where to start creating a jig plate for these cases.

[Snapper]

No idea where to start creating a jig plate for these cases.

If it's specific for one part then your imagination is the limit. You just need a method to quickly and accurately place the part on the jig, some sort of reference to touch off, and a way to hold it. As a couple of examples, if you have holes or can find somewhere to put extra holes for dowels on what will be the bottom face that's a really easy and accurate way to do it. You could cut a pocket in the plate for the part to sit in. Could even just have a straight edge in each X and Y to butt the part up against. And just a way to hold it down, step clamps, bolts directly through any through holes etc.

The amount of time this could save you compared to flipping and touching off each part in the vice for every single op could be substantial, leaving you only needing to set up for each op once at the start of the day. So you'd use some sort of reference in your vice to line stock up with and cut so many parts from one side in the vice, then set up once on the jig plate and do all the flip side. If you see what I mean. Save your work offsets for your vice and jig work as G54 and G55 then when you start your machine the next day all you have to do is chuck up your edge finder/probe or whatever you use and make tiny adjustments to account for the error in the home switches at the start of the day.

For batch work on a machine like this with the tools you have I can't think of a better way to do it.

[JOGARA]

This style of vice is lower - https://www.cutwel.co.uk/work-holdin...-machine-vices
However I've still to find more reasonably priced version.

I checked them out as like you say they are lower. But they are costly and I can't make my own soft jaws for them

[m_c]

It seems to the ideal vice for what I'd like, but I'm holding of in the hope Cutwel have a promo on them at some point, or until I find something similar in a 5-6" jaw version.

You can make anything with the right tools ;-)

[JAZZCNC]

It seems to the ideal vice for what I'd like, but I'm holding of in the hope Cutwel have a promo on them at some point

Give Cutwell a ring they will give you good deal. (ask for Harriot Dootson)

[Snapper]

Cutwel had the Gerardi vices on offer in December, I got one. Wish I'd got two. Or thee. Or four

You can set the Gerardi vice up how you want, it doesn't need to have the angle jaws, you can get them with flat jaws, serrated jaws or whatever you want. It's a modular vice and there's a whole tonne of accesories for them. You've still got the issue of the vice bending your work, and in the case of the Gerardi the angle jaws would cause it to bend quite badly (the angle is there to add downforce for pulling the work down to ensure it clamps true repeatedly).

A dedicated fixture really is the way to go here IMO.

[JOGARA]

What model of those extrusion channel nuts do I need for this X6-2200L?