face milling

I have a arc euro three insert face mill cutter and using on a SX3 mill.I have been taking .5mm cuts and with new inserts and the head wags side to side at 400 rpm.Is the cut to deep and the feed to fast.I find that my flycutter at 75mm sweep at.5mm and 400rpm creates barely a murmer at the head ,can someone put me right.Feed for both was 1" per minute.

Frank

Hi Frank what diamiter is the cutter and what style is the tip and what material are you cutting. It sounds like you are running it to slow perhaps a picture may help if you can post as well.

David

The diameter of the face cutter and workpiece width may have some bearing on feed rate and depth of cut? Is that 75mm too? Your fly cutter, all things being equal, will be cutting three times the effective tooth load of the three-insert jobbie.

If the tool is Ø75mm and the material is mild steel then you should be running at about 300rpm and upping the feed to somewhere between 5 and 10 inches per minute. You are over speeding and under feeding which results in rubbing not cutting.

400 rpm and three cutting edges is 1200 passes per minute at the cutting face. In that same minute you are travelling 1" so the result is each tooth is trying to cut off 1/1200" which is 0.00083"/0.021mm. This is definitely going to be rubbing when using carbide inserts.

Martin C

Have you got a link to the tool, or a photo ? Asking because i bought a cheap 3 insert face mill once (Not from Arc) and it was useless, could never get a decent cut from it, and my mill is industrial sized.

Try running it with one insert and see if that makes any difference.

Using one tooth instead of three is the same effect as upping the feed by a factor of three. Maybe you should have tried a faster feed than you were using.

On Monday I was using a Ø16mm 2 insert cutter on aluminium at 1300rpm and 350mm/minute feed. This produces large chips not small particles of debris and with a very nice finish.

Martin C

PS if there is a runout error of maybe 0.002" from the highest to the lowest insert then the 400rpm and 1" per minute feed will result in only one tooth cutting, one possibly rubbing and one not doing anything apart from sweeping away debris.

Edited By Martin Connelly on 30/12/2020 09:55:28

Sounds more like you are using one of the indexable endmills that take the triangular inserts that ARC no longer do than the current face/shell mills.

I've had a Glanze version of the same too in 40mm dia and get a decent finish with that on steel and cast iron. Probably run that at 800rpm and feed of approx 150mm/min. If you have a 50mm dia one then around 650rpm would be a reasonable starting point and same 120mm/min feed

That is correct Jason it is 40mm.I have been milling 2" flat mild steel.

This is a "Little Hogger" Ø25 two insert milling tool. The inserts are as plain as you can get with a flat face. The workpiece is just a bit of scrap mild steel. This is what correct feeds and speeds does.

RPM 860

Feed 150mm/min

Depth of cut 0.5mm

Machine is the much maligned round column mill/drill.

Martin C

So this is my 40mm one running at 800rpm, feed of about 200mm/min, 0.5mm DOC doing a full width pass on some 40mm wide EN3. Bit of gear noise from the head at the end of the cut as the engagement falls off and does not quite pass the Sharpie test but not too bad a finish, would benifit from a finishing pass at about 100mm/min.

Edited By JasonB on 30/12/2020 15:40:38

Tank you all, I was feeding to slow and rpm not fast enough ,it is great to have such a quick response and a great forum.

Frank

I have a Ceratizit 50mm shell mill with 5 inserts and on the side is the maximum rpm. 12200 maximum, and in the Ceratizit pdf it says that the screws should be changed at the same time as the inserts if that speed is used. The inserts have either 4 or 8 stations before they are worn out. I can only manage 3000 rpm and the depths and feed rates depend on the power available. Most hobby machines run out of speed before the carbide tools do.

Well be it right or wrong it seems that I run my 2 insert 25mm diameter end mill quite a bit faster than what the books and charts suggest. I have only been machining for a couple of years so not that much experience but I tend to let the machine (mill and lathe) the tooling, the cut depth, speed and feed and the finish point me in the right direction.

With the 25mm end mill I run at the mills top speed 2500rpm for cuts up to 1.5mm deep, the mill and the inserts are happy, the finish is excellent so I don't query it.

With steel and cuts up to 1.0mm deep I run with 1750rpm on EN1A and 1500 on EN3, 1250 to 1500 on EN8 though with a small part recently in EN8 the cutting area was quite small and 0.5mm deep so I went with 1750 and it was fine with a very good finish.

My thinking is that the tool is a 2 carbide insert cutter and it should be run in the higher speeds but I could be wrong and quite prepared to be corrected but as I say I am basing it on results that I get with the tool.

Carbide will quite happily cope with high speeds but two issues are that as your rpm increases the feed rate needs to go up to keep the cutting process going and you have hotter chips flying farther and faster. If you only have manual feed or limited feed rates it is better to reduce the rpm to suit. At 2500rpm and 2 edges you would need to feed the work at about 450mm/minute, hard work if you are cranking a handle to do it.

A lot of machines in the hobby world have limited power so the compromise is between speed and torque means that lower speeds are chosen to give higher torque for cutting (geared or pulley drive speed selection). With electronic speed control lower speeds can reduce torque so they may need setting to a higher speed to get the best results.

Unless you have flood coolant rubbing creates heat in the tooling and workpiece that may cause issues if you are trying to achieve an accurate size. If you look at my video above you can see that I am producing chips that are going blue so I am in the good working range for the carbide inserts. The workpiece and tooling was not noticeably warm after the process as the chips carried the heat away.

Martin C

When the edges are sharp, they do not impart much heat to the work, but if the work gets very hot, it is time to look at the insert. It may be possible to sharpen the fronts of the triangular inserts on a diamond lap. I have one which is about 150 x 70mm and double sided, 400/1000 grit. If used wet, that type could give the inserts a new lease of life. For a twin insert cutter, you would have to sharpen them in pairs and match the thickness so they cut evenly in the tool.