Machining part, advice, what should I be doing?

[chris123]

Yep Im new and still learning
This part is 6.5" x 1.5" x 10mm

I am using a 4mm flat end mill to do everything
I need to do profiling and facing
I'm currently running at 24ipm at 7500rpm and cutting 0.02" each time

Is there a specific tool bit I should be using for facing and profile?
Should I be using a larger or different toolbit? 6mm 8mm 10mm?

Here is the part



This is the machine, Taig bench mill

[christinandavid]

If you are happy with it leave it as is.

If its taking too long turn the feed up.

If your cutter burns out turn feed down, take deeper cuts.

If it breaks your cutter try a fatter one.

If it shakes your machine apart change your milling strategy.

Repeat sequence until you run out of components/cutters/money/time.

DP

[fly_boy_bc]

What is making you think that you need to use other tooling? Is it the "grooves" in the workpiece?

I have the exact same Taig micro mill that you have. I ordered mine from Microproto Systems. I have only had it a week and I am a complete noob.

I suspect that a flat end mill of a larger diameter will eliminate/reduce the scaloped effect. But I am a noob so wait for more experienced answers.

In any event I will be watching for your answers. They will certainly help me in the long run.

What is that piece you are making anyway?

Gary B in BC doing CNC

[chris123]

Originally Posted by christinandavid 1. If you are happy with it leave it as is. 2. If its taking too long turn the feed up. 3. If your cutter burns out turn feed down, take deeper cuts. 4. If it breaks your cutter try a fatter one. 5. If it shakes your machine apart change your milling strategy. Repeat sequence until you run out of components/cutters/money/time. DP

1. It takes way too long I'd to machine it faster
2. I cant turn the feed up thats the machine max speed
3. Taking deeper cuts the aluminium just gums up jams the tool bit and breaks it
4. I will try a fatter cutter, 8mm
5. The machine is not shaking

[chris123]

Originally Posted by fly_boy_bc 1.What is making you think that you need to use other tooling? Is it the "grooves" in the workpiece? 2. I have the exact same Taig micro mill that you have. I ordered mine from Microproto Systems. I have only had it a week and I am a complete noob. 3. I suspect that a flat end mill of a larger diameter will eliminate/reduce the scaloped effect. But I am a noob so wait for more experienced answers. 4. In any event I will be watching for your answers. They will certainly help me in the long run. 5. What is that piece you are making anyway? Gary B in BC doing CNC

1. No, its the time it takes and I cant seem to cut deeper as it just breaks the tools bits
2. This is only mill Ive ever seen and used in real life, I can not judge on how good or bad it is
3. I will try a larger end mill
4. Yep, most people here have larger mills and unless Im doing something wrong, doing what they say is not possible
5. Its a guide rail

[Algirdas]

use coolant. If You arrange just powerfull air blow, it helps very much.

[chris123]

to get it to what it currently can do i use wd40, air is not enough

[Algirdas]

just kerosine is enough. WD40 is intended for different use, too expensive here

[christinandavid]

Change your strategy to helically mill a 2xD clearance hole to full depth, then mill out the pocket required in a spiral/trochoidal fashion using the full length of the cutter but a small radial overlap. This strategy can be faster and is much gentler for the cutter/machine than a full diameter cut. Not as much heat will be generated, the swarf will then have somewhere to go, you will not knacker the very end of the cutter so much. A ripper form cutter will take more of a beating if the side finish is not too critical. If it is an end mill to finish the tab.

DP

[fly_boy_bc]

Originally Posted by chris123 1. No, its the time it takes and I cant seem to cut deeper as it just breaks the tools bits 2. This is only mill Ive ever seen and used in real life, I can not judge on how good or bad it is 3. I will try a larger end mill 4. Yep, most people here have larger mills and unless Im doing something wrong, doing what they say is not possible 5. Its a guide rail

1...How long did it take to get to the point you are at in the pictures? Rememer it's cut deeper AND slower NOT just deeper.
2...All i have ever heard tells me that the Taig is a superior machine for the size. 1/8 inch cuts in steel with a 1/8 inch end mill. SOLID.
3... Yes that is the first thing I would try it should help the finish too. Is it a nice new sharp endmill?
4...Deeper AND slower, use correct coolant, are you using air or kerosine? WD40 is barely useful. Yes you can.
5...For what?

[chris123]

Originally Posted by fly_boy_bc 1...How long did it take to get to the point you are at in the pictures? Rememer it's cut deeper AND slower NOT just deeper. 2...All i have ever heard tells me that the Taig is a superior machine for the size. 1/8 inch cuts in steel with a 1/8 inch end mill. SOLID. 3... Yes that is the first thing I would try it should help the finish too. Is it a nice new sharp endmill? 4...Deeper AND slower, use correct coolant, are you using air or kerosine? WD40 is barely useful. Yes you can. 5...For what?

1. It takes about an hour from start to finish. The tool bit I'm using is brand new. When I cut deeper e.g. 0.03" the aluminium gums up to the point where it jams the machine and breaks the bit. Slower as in RPM and IPM
2. I think its more to do with the type of aluminium Im using, I've cut through 0.07" dry and with the same sized bit on different aluminium
3. It is new because I broke several bits before I worked it out
4. air does not work, wd40 does, is kerosine classed as correct coolant?

[awerby]

Is there any reason you're using this particular stuff? Most machinists prefer a heat-treated alloy, like 6061 T6. Non-heat-treated aluminum tends to be gummy, cuts poorly, and welds itself to the cutter

From the looks of the cut, it seems like your mill's out of tram. If there's "stair-stepping" side-to-side, then you need to square it up by loosening the nut on the back and using a machinist's square to establish a true 90 degree angle of the column to the bed. There are more elaborate tramming routines, but that should get you most of the way there.

You should do the majority of the stock removal with the largest cutter you can. There are 10mm ER-16 collets available. If you have details it can't reach, follow up with a finish cut using a smaller-diameter tool. Christiandavid had some good suggestions on this. Finish cuts in aluminum come out cleaner if you use "climb" cutting rather than "conventional".

Andrew Werby
www.computersculpture.com