[Memran]

Well after some time setting up, I've actually put it to some use!

My 1st practice/test run on some scrap MDF:


Added spline shape for my fitting and cut in aluminium:

Pic shows the reason for the spline.

Nice tight fit!


Assembled to an old, used crank arm:


I'll be fitting it to my bike shortly

For a 1st trial of Gcode programming, and 1st guess at a nice feed/speed, I think it came out ok It seems like the X1 can cope well with an 8mm end mill, 0.5mm deep, 120mm/min @ 2000 rpm, dry. I don't think I could push too much more than this so the whole thing took about 2 hours 40 mins to cut. Including tool changes to a 3mm end mill for the spline.

SO.. question 1. Any suggestions for increasing speeds and feeds, or is the speed I chose all I can expect from the little machine?

Now for the question 2! Why do G02 and G03 not function when in polar coordinate mode? The spline part could have been written so much simpler in polar...

[Pres]

SO.. question 1. Any suggestions for increasing speeds and feeds, or is the speed I chose all I can expect from the little machine?

Now for the question 2! Why do G02 and G03 not function when in polar coordinate mode? The spline part could have been written so much simpler in polar...

Congrats on a nice looking part.
Speeds/feeds seem ok for the x1 machine (light cuts are best)
You might want to try squirting the cutter/part with some WD-40 (or kerosene) to see if it improves cutting action.
(like smoother cut - better finish)
Did you climb cut for the finish passes?

Your polar problem seems like it is just a control restriction.
What are you using?

Excellent 1st part on your X1.
I think the "key" to an X1 is simply that it can be done.
If you want to do it faster, then use an X3/Tormach/HAAS/etc.
(your wallet then becomes the main limitation

Pres

[matsuura]

Look good!

A trial or bmx?

[Memran]

Thanks

Did you climb cut for the finish passes?

Hmm what does that mean?

Look good!

A trial or bmx?

Trial

[matsuura]

I'm also a trial and dirt jump guy best sports in the world.

[Memran]

Your polar problem seems like it is just a control restriction.
What are you using?

Mach2

[edo]

Nice Piece!

Originally Posted by Pres View Post
Did you climb cut for the finish passes?
Hmm what does that mean?

Check out the Mini-mill users guide at LMS for a very good explanation of climb milling.
Ed

[digits]

That is a very nice looking part! :cheers:

You could probably cut a bit faster with coolant - it also makes things quieter, and makes the finish better, but it is a bit of adventure as you'd have to build a full enclosure to contain all the liquid and chips. I'm on my 3rd table/enclosure so far, and still not 100% happy with it!

I tend to cut fast but shallow as I think this reduces the cutting forces - though I can't seem to find the formula that made me think that. Last night I was cutting at 600mm/min @ 2000 rpm with a 10mm dia 4-flute mill with a 0.1mm depth of cut - seemed to work pretty well.

Pres: How can you ensure climb milling on an interpollated path? Surely some quadrants of a circular shape will be climb milled, and others conventionally?

[Pres]

Pres: How can you ensure climb milling on an interpollated path? Surely some quadrants of a circular shape will be climb milled, and others conventionally?

Not sure what you mean by "interpollated path" but usually the extra stock is (or should be) staying on one side of the cutter throughout one operation.
Conventional milling can be defined as when the next flute on your end mill is coming in about tangent to the cut made by the prior flutes cut.
i.e. moving towards your end mills cutting direction.
Benefit: less impact of flute against part material.
Disadvantage: Swarf can be drug across just cut surface and tool deflection (there ALWAYS is some) will be into the finish surface.

Climb milling can produce a nicer finish surface.
Benefit: swarf (chips) are usually deflected away from part much better.
Tool deflection is ALWAYS away from finish surface - lessening the chance of undercut on the finish surface.
Disadvantage: more tool bit impact and vibration -particularly during roughing cuts.

[digits]

Not sure what you mean by "interpollated path" but usually the extra stock is (or should be) staying on one side of the cutter throughout one operation.
Conventional milling can be defined as when the next flute on your end mill is coming in about tangent to the cut made by the prior flutes cut.
i.e. moving towards your end mills cutting direction.
Benefit: less impact of flute against part material.
Disadvantage: Swarf can be drug across just cut surface and tool deflection (there ALWAYS is some) will be into the finish surface.

Climb milling can produce a nicer finish surface.
Benefit: swarf (chips) are usually deflected away from part much better.
Tool deflection is ALWAYS away from finish surface - lessening the chance of undercut on the finish surface.
Disadvantage: more tool bit impact and vibration -particularly during roughing cuts.

Sorry - I meant if your mill is running some complex curved path, can it always be cutting towards the the stock? I had to think about it for a while, but I think I see how it works now.

[cyclestart]

Basic climb milling definition
http://www.mfg.mtu.edu/cyberman/mach...ing/index.html

Backlash is the enemy when climb milling. If you ever use this method on a conventional machine make sure you understand the precautions that need to be taken. To get a visceral [1] feel for the physics involved place your left hand with the palm facing you and spin an endmill with the fingers of your right hand. Pretend the hand is a work piece.

[1] Don't cut yourself. No need to get that visceral

[Memran]

Thanks for the positive comments!

Yes, climb milling. From when the machine was still manual I noticed the difference in the cut depending on fed direction. I just didn't know it had a name!

I am noticing backlash a lot now, especially in circles. I've been looking at ballscrews, but I'm not sure its worth spending more money on such a slow machine.

[edo]

If you're able to quantify the amount of backlash, Mach 2 should be able to compensate for it. I know Mach 3 can.
Ed

[digits]

Thanks for the positive comments!

Yes, climb milling. From when the machine was still manual I noticed the difference in the cut depending on fed direction. I just didn't know it had a name!

I am noticing backlash a lot now, especially in circles. I've been looking at ballscrews, but I'm not sure its worth spending more money on such a slow machine.

I know what you mean I'm not too impressed by my X1's circle cutting ability either - but right now, my biggest problem is the puny 150W motor and the fragile gearbox.

If you're tempted to go for a bigger mill, my advice would be to do plenty of research so that you don't end up underwhelmed again, but also to do it before you have £500 worth of tooling that you can't take with you. I don't know what part of the UK you're in, but there are several model engineering fairs on in the summer that you might be able to see some of the larger machines at.