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

[JOGARA]

If you're using fusion, use the adaptive tool path for clearing metal out. I've cut down to 13mm Doc with my OMIO, between 0.3/0.4mm step over. You can go wider if you're cutting shallower. Better for tool life too as you're using more of the tool than just constantly using the tip.

Skim off the top of the part so it's all perpendicular to your gantry and spindle then your chamfers should be even. A light rub with sandpaper and a quick splash with polish to remove the tool marks and it will look much better than the grainy texture on the top of the extrusion as well.

I'll give that a go tomorrow.
I am cutting 15mm deep so try 7.5mm at around .5-.6mm step over?

[Snapper]

I'll give that a go tomorrow.
I am cutting 15mm deep so try 7.5mm at around .5-.6mm step over?

Should be fine with that. Just play a bit and see what works. One tip, try and square your spindle to the vice, don't spend hours getting it as precise as humanly possible, just 2 minutes with a dual gauge to get it there or there abouts as it will shift out of alignment anyway within about 30 seconds. I do it before every job I want to look half decent. But if you've been jogging into things it's likely to have got knocked well off and that's an invitation for bad chatter.

Also make sure your spindle, collets and nut are squeaky clean for your finishing tools, and if your collet is old and been bashed about, get a new one. They're only tuppence on eBay.

[JOGARA]

8mm DOC, 0.5mm max stepover.
Cut fine, no noise, looks like I can go deeper.
Going to attempt 1mm. Can always pull it back.

This is much better than the 1hour+ than before. Down to 15mins now :)

The spindle is out but only by a hair. I can feel on the contour pass a slight line going around 2 sides of the part.
I have lowered the contour pass to take 4 depths instead of 2, this fixed that problem last time.










I am also getting this again on the contor. I have a 10mm finishing overlap. But I used default lead-in. I have upped that to 2mm. Hopefully that stops that.



And yes, I forgot to go -0.1mm on the contor pass so there is a bur going around the bottom of the part. The roughing pass went -0.2mm, so I normally set -0.1mm for the finishing endmill.

[Snapper]

Are you using tooling plate to cut your parts from? That must be costing you a bloody fortune!

[Chaz]

Are you using tooling plate to cut your parts from? That must be costing you a bloody fortune!

Its not much more than standard Alu. The fact that its reasonably flat has many benefits.

[JOGARA]

Its not much more than standard Alu. The fact that its reasonably flat has many benefits.

This /\


Wanted to reduce my machining time so was faster to have the top and bottom already finished.
That being said, sometimes one side does have marks on it that won't work for a finsihed product.
Most of the time it is only on one side so I mill into that side while leaving the pretty face the to outer face that I see.

What I might be moving towards is bar stock so I can grab it in my vice and not have to glue my stock to a large plate.
Though I like maching the top and bottom at the same time as there are 4-5 tool changes.

If I have ATC then that would not be a problem...

[Snapper]

Its not much more than standard Alu. The fact that its reasonably flat has many benefits.

Maybe for little odd jobs but for production? At a guess it's about 50% dearer than just buying a bar isn't it?

[JOGARA]

Maybe for little odd jobs but for production? At a guess it's about 50% dearer than just buying a bar isn't it?

Going off AW, 5083 bar worked out more expensive than Plate.
Both cut to size.

This is AW though...

[JAZZCNC]

Maybe for little odd jobs but for production? At a guess it's about 50% dearer than just buying a bar isn't it?

Nowhere near 50% more like 10% if that and the savings in machine time can easily justify that. I rarely buy bar stock anymore