Feeds and speeds. Some tips for a newbie please!

[Richard]

So anyone any ideas why that carbide endmill is showing so much wear?

Feeds and speeds were not a million miles away from G-Wizard.

I am surprised how ali can erode carbide so easily!

[Chaz]

So anyone any ideas why that carbide endmill is showing so much wear?

Feeds and speeds were not a million miles away from G-Wizard.

I am surprised how ali can erode carbide so easily!

We havent ruled out that you are using cheap / crap endmills. Try with something semi decent first (https://www.shop-apt.co.uk/) would be the supplier for me for something 'OK'. Id select a 2 flute uncoated endmill to start with. Plus, as Mr Ward suggests, the material might be the problem. Dont focus on the blunt endmill.

[Snapper]

Thanks buddy, I have listed it for sale. But also reminded the seller I bought it from that they must provide me with a solution as to why it doesn't do what they promised.

As for parts I might drop it for a while, have a break and finish up all the drawings in fusion. I wanted to make a scale hawker hurricane in its entirety with a 1.5mtr wing span. And then maybe a Lancaster. But watch tools were my main project. Haven't managed one yet.

I'll stay on the boards keep watching, reading and learning. Then maybe if things get better buy a proper mill and convert it to cnc.

Sent from my F8331 using Tapatalk

What machine is this Dave? Sounds like a chinese ebay special router.

They don't really work well out of the box and need a bit of wiring doing to get them to work fairly stable. Spindle or machine frame needs earthing, a star point earth helps too, and the spindle cable at least pretty much needs swapping for a shielded CY cable, otherwise you will have all sorts of havoc. Doesn't hurt to do the switch and stepper wires either although not really neccesary.

[Snapper]

So anyone any ideas why that carbide endmill is showing so much wear?

Feeds and speeds were not a million miles away from G-Wizard.

I am surprised how ali can erode carbide so easily!

Is that end mill coated? Looks like it might have tialn coating, which will cause build up pretty quickly, that's probably not erosion but almost certainly a build up of aluminium on the cutting edge. You want uncoated cutters really for ali. And yes find out what the material is, even different batches of the same grade can cut differently but stuff like 1 series ali is horrible for machining.

[Dave_stoke]

What machine is this Dave? Sounds like a chinese ebay special router.

They don't really work well out of the box and need a bit of wiring doing to get them to work fairly stable. Spindle or machine frame needs earthing, a star point earth helps too, and the spindle cable at least pretty much needs swapping for a shielded CY cable, otherwise you will have all sorts of havoc. Doesn't hurt to do the switch and stepper wires either although not really neccesary.

It is an eBay special lol. It's the cncest 3040T.
Where do I earth it from to?

Sent from my F8331 using Tapatalk

[Richard]

Is that end mill coated? Looks like it might have tialn coating, which will cause build up pretty quickly, that's probably not erosion but almost certainly a build up of aluminium on the cutting edge. You want uncoated cutters really for ali. And yes find out what the material is, even different batches of the same grade can cut differently but stuff like 1 series ali is horrible for machining.

OK, I'll get a 2 flute uncoated from APT and see how it goes. The cutters I have are coated but I don't know what with.

The part I was machining is the bed of the machine, so no idea what grade it is. I just wanted it flat(er) and level.

Once I get the new 2 flute cutter, is 6k rpm and 500mm/min, dry, still in the right ball park for taking a shallow finishing cut at say 90% engagement?



Just for my own interest, if there is build up on the tips of the cutter, how does that erode the tip?


Thanks for the input!

[Chaz]

OK, I'll get a 2 flute uncoated from APT and see how it goes. The cutters I have are coated but I don't know what with.

The part I was machining is the bed of the machine, so no idea what grade it is. I just wanted it flat(er) and level.

Once I get the new 2 flute cutter, is 6k rpm and 500mm/min, dry, still in the right ball park for taking a shallow finishing cut at say 90% engagement?



Just for my own interest, if there is build up on the tips of the cutter, how does that erode the tip?


Thanks for the input!

What is the highest speed your spindle can rotate at?

[Snapper]

It is an eBay special lol. It's the cncest 3040T.
Where do I earth it from to?

Sent from my F8331 using Tapatalk

Every chinese spindle I have seen actually has a 4 pin plug on top so you can hook that up on the bottom to a bolt inside the spindle housing (under the cap) and then if you get a 4 core CY cable for your spindle you can run your earth with that, which is the best and tidiest way to do it imo. For a quick fix for now just take any bolt out of the frame (away from the cutting area and any moving parts) and get a piece of cable, crimp a ring terminal on the end of it and bolt it down to the frame, connect the other end to earth. That 'may' help your problems a bit short term, but shielding that spindle cable is going to be of more help. VFD emits a lot of EMI, and doesn't play nicely with USB or other low voltage electrics.

Your problem could also be mechanical, misalignment somewhere or something, or even a weak PSU that is struggling to drive 2 axes properly simultaneously. The power supplies they send out with these things really are a pile of crap (mine ended up setting on fire )

[Chaz]

Every chinese spindle I have seen actually has a 4 pin plug on top so you can hook that up on the bottom to a bolt inside the spindle housing (under the cap) and then if you get a 4 core CY cable for your spindle you can run your earth with that, which is the best and tidiest way to do it imo. For a quick fix for now just take any bolt out of the frame (away from the cutting area and any moving parts) and get a piece of cable, crimp a ring terminal on the end of it and bolt it down to the frame, connect the other end to earth. That 'may' help your problems a bit short term, but shielding that spindle cable is going to be of more help. VFD emits a lot of EMI, and doesn't play nicely with USB or other low voltage electrics.

Your problem could also be mechanical, misalignment somewhere or something, or even a weak PSU that is struggling to drive 2 axes properly simultaneously. The power supplies they send out with these things really are a pile of crap (mine ended up setting on fire )

Also, where are you based? Someone from this forum might be able to pop in and take a quick look.

[Snapper]

OK, I'll get a 2 flute uncoated from APT and see how it goes. The cutters I have are coated but I don't know what with.

The part I was machining is the bed of the machine, so no idea what grade it is. I just wanted it flat(er) and level.

Once I get the new 2 flute cutter, is 6k rpm and 500mm/min, dry, still in the right ball park for taking a shallow finishing cut at say 90% engagement?



Just for my own interest, if there is build up on the tips of the cutter, how does that erode the tip?


Thanks for the input!

Noooo. Don't cut the bed.

Get a board, sheet of ali, whatever you want to use and stick it on top. The bed is made of several independent pieces of extrusion and even if you machine it 'flat' they will flex independently anyway. Also you're then tied in to the cutting area, you can't really load a bigger piece in and clamp it outside the work area.