DM 45 deep cuts

[morrisman]

What is the secret to taking deeper than 1.5 mm deep cuts in mild steel . With the 60mm 5 cutter face mill, the machine shudders and is saying , thats my limit . I have tried different speds and feeds but the same result :(( Am i asking ot to do too much ?

At the moment if I want to remove say, 10mm , I have to take 4-5 passes to do it .

Mike

[Dave J]

With a 60mm face mill that might be your limit. Does the motor sound like it's laboring?

Dave

[morrisman]

With a 60mm face mill that might be your limit. Does the motor sound like it's laboring?

Dave

Dave

The motor isn't laboring but the face mill itself struggles and it makes a harsh sound and the whole machine vibrates more than it does with a shallow cut .

So with the narrower 4 flute end mills , say 20mm diameter , deeper cuts such as 3mm are possible at slower speeds like 100 rpm ?

Mike

[pipeclay]

Depending on the type of cutter you are using (different face mills perform differently) or the tips you are using you should be able to get around 3mm depth 1000 rpm and around 100mm p/mim or higher feed.
Even with your 20mm endmill you should be able to take 6 to 10 mm depth of cut at around 300rpm.

[Dave J]

Does your face mill have positive rake inserts? I was going to say 100rpm is to slow for that size, but Pipeclay has fixed you up there.

Here is a rough guide to go off that I posted a while back

(Cutting Speed x 4) / Tool Diameter = RPM

Cutting speed 90 (for steel from the list below) x 4 / divided by the cutter diameter in inches

So for a 1/2inch end mill
90 x 4 / 0.50=720 rpm

Here are some other cutting speeds, just replace the 90 with these for the type of material your cutting.

Aluminum 300
Brass/ Bronze 150
Copper 100
Cast iron soft 80
Cast iron hard 50
Mild steel 90
Cast steel 80
Alloy steel hard 40
Tool steel 50
Stainless steel 60
Titanium 50
Plastic 300-800
Wood 300-500

Hope that helps
Dave

[Jayson]

Hi Mike,

I have a ZX45 and on mine 1.5mm IS a deep cut. It just won't handle anything deeper in steel.
Hopefully more people with a similar machine can give you guidance.

Jayson.

[pipeclay]

It appears that the Dovetail Mill Drills may not be capable of heavier cuts,perhaps the Round Column Mill Drills are more ridgid.

[morrisman]

Ok on the formula :2tsup:

I will have to wait til the VFD is up and running , I only have 6 speeds at the moment . 100 rpm is the lowest .

The machine performs well is many respects , but it does have major limitations .


Mike

[morrisman]

Depending on the type of cutter you are using (different face mills perform differently) or the tips you are using you should be able to get around 3mm depth 1000 rpm and around 100mm p/mim or higher feed.
Even with your 20mm endmill you should be able to take 6 to 10 mm depth of cut at around 300rpm.

I have always suspected that the tips that came fitted on the cutter are of dubious quality .

I will have to invest in some better quality 422 tips .

MIKE

[Dave J]

Hi Mike,

I have a ZX45 and on mine 1.5mm IS a deep cut. It just won't handle anything deeper in steel.
Hopefully more people with a similar machine can give you guidance.

Jayson.

Pipeclay's machine is similar, but a round column mill. He has a lot of experience in machining, so take those figures as a guideline to head for.

Dave

[Ueee]

I have a HM50, hafco's smallest turret mill. I use several iscar helli2000 cutters for facing and as endmills. Even with this size machine a 50mm 6z cutter can only cope with a 2mm deep cut before it looses that buttery soft feel that produces nice long spiral shavings and starts to chatter and produce chips. My 30mm cutter (4z) with the same tips and geometry can go to about 5mm, my 20mm (3z) can go pretty much full depth of the tip (10mm i think)

Oddly, if i lock the quill of the machine i get a "knocking" sound from the head (up high- like its the spline on the pulleys) which transfers right down to the cutting edge.

Also, is your machine in tram? a slight tilt can create forces on the cutter that its not designed for, and the larger the cutter the greater the effect.

[Dave'H]

Hi,

At the end of the day it all comes down to the rigidity of the machine. I would consider a 1.5mm cut on my RF30 mill a little to much for it. I realise your frustration taking off 10mm in 4 / 5 cuts, but it would take me 10 passes.

These type of mills are for small workshops / home shop use, and so do have their limitations, nevertheless I still think they are good milling machines.

Dave'H

[Dave J]

I have a HM50, hafco's smallest turret mill. I use several iscar helli2000 cutters for facing and as endmills. Even with this size machine a 50mm 6z cutter can only cope with a 2mm deep cut before it looses that buttery soft feel that produces nice long spiral shavings and starts to chatter and produce chips. My 30mm cutter (4z) with the same tips and geometry can go to about 5mm, my 20mm (3z) can go pretty much full depth of the tip (10mm i think)

Oddly, if i lock the quill of the machine i get a "knocking" sound from the head (up high- like its the spline on the pulleys) which transfers right down to the cutting edge.

Also, is your machine in tram? a slight tilt can create forces on the cutter that its not designed for, and the larger the cutter the greater the effect.

I have a HM52 and had the same problem along with a lot of other guys. I did a right up on how to fix it and also one on fitting a tapered top bearing which I think improves it as well.
http://www.woodworkforums.com/f65/another-idea-bad-fitting-splines-mill-126490/
After I did mine Ray did his and it fixes the problem of the knocking you are hearing.

This is the one on the tapered bearing.
http://www.woodworkforums.com/f65/changing-top-quill-bearing-taper-one-hm52-126514/


Dave