High speed toolpaths

[camtd]

Are there toolpath options for Mastercam like this?

http://64.26.25.102/wms/High_Speed_V...pen_Pocket.wmv

Are there real benefits to this style path?

[Geof]

Originally Posted by camtd Are there toolpath options for Mastercam like this? http://64.26.25.102/wms/High_Speed_V...pen_Pocket.wmv Are there real benefits to this style path?

I have no idea if Mastercam has this feature but I can say very definitely there are advantages to this kind of toolpath. Wade your way through this thread and you will see why I say this.

Now I'm a believer; you can mill C1018 at 800 FPM

[Donkey Hotey]

Yes, Mastercam has high speed loops as a type of cutting path. I'm a nOOb when it comes to this stuff but these are the advantages as I understand them:

• The cutter engagement is more constant than more traditional cutter paths. There are no 'corners' where the cutter goes from 45 degrees of engagement to 135 degrees of engagement. If you think about the cutter's flex, suddenly hitting a 90 degree corner in a pocket will cause the load to go wayyyy up. That's going to twist and distort the endmill. At a bare minimum, that could create coining marks in the corner transitions. At worst, it could snap a cutter.
• You generally have to program your pockets around the peak loads that the cutter experiences in the corners. Since there are no longer 'corners' in your path, you can program closer to the limits of the cutter (depth & radial engagement). That means more efficient material removal (if you apply it properly).
• The machine isn't making any sudden axis changes. Because the movements are circular, the table isn't making sudden starts & stops at the end of linear pocket moves. The also helps to reduce coining marks on the part (caused by the machine bouncing slightly when the table has to come to a screeching halt at the end of a pass).

OK, that's my nOOb opinion on the matter. Is this more of a general machining question or are you shopping for Mastercam?

[mactec54]

Hi Camtd

Yes this is HSM at its best the type of machining is called Trochoidal machining/toolpath I don't no what Mastercam has but Gibbs sure has had it for many years as one of there many features, Tt is one of the fastest way to remove a lot of metal/plastic etc I use it when ever I can

[tobyaxis]

Try reading here for HSM in Mastercam.

http://www.mastercam.com/Products/Mill/Default.aspx:)

[Geof]

Originally Posted by Donkey Hotey ....I'm a nOOb when it comes to this stuff but these are the advantages as I understand them: [LIST][*]The cutter engagement is more constant than more traditional cutter paths. There are no 'corners' where the cutter goes from 45 degrees of engagement to 135 degrees of engagement....

I think you are correct with the "no 'corners'" comment but I think a big advantage is exactly opposite to more constant cutter engagement. When machining steel at very high speeds the trochoidal tool path allows the cutter to leave the cut and cool down, which is what allows the very high feet per minute and chip loads possible with this approach.

This type of machining means I have to recant on my dogmatic statements in the past that when hand coding is possible it will probably be faster than a CAM program. When the material being machined is steel and trochoidal toolpathing can be applied a CAM program will probably run much faster than a hand coded program. (Aaaaargh!!!! do you realise how painful it is for me to admit this?)

[Donkey Hotey]

Don't worry, Geof, your statements were true for the types of parts you were making. Your parts and fixtures are just getting more complex.

Yes, your comment about the cutter cooling down is another good one.

I've only used the trochoidal motion a couple of times. The problem is that the few times I've had the opportunity, the part was really too small to take advantage of it. The cutter was just wobbling around in a narrow pocket and there wasn't enough room to keep the cutter engagement constant.

[tobyaxis]

Originally Posted by Donkey Hotey Don't worry, Geof, your statements were true for the types of parts you were making. Your parts and fixtures are just getting more complex. Yes, your comment about the cutter cooling down is another good one. I've only used the trochoidal motion a couple of times. The problem is that the few times I've had the opportunity, the part was really too small to take advantage of it. The cutter was just wobbling around in a narrow pocket and there wasn't enough room to keep the cutter engagement constant.

I hear that. We never get to have any fun unless we venture off to another shop.

[Geof]

My parts are also nearly always aluminum where the advantages do not really apply.

There are some steel parts we do but they would probably fall into your category of the cutter wobbling around without enough room to do the proper thing.

I just find it fascinating how fast you can chew material away when things fall in the correct place.

[tobyaxis]

Originally Posted by Geof My parts are also nearly always aluminum where the advantages do not really apply. There are some steel parts we do but they would probably fall into your category of the cutter wobbling around without enough room to do the proper thing. I just find it fascinating how fast you can chew material away when things fall in the correct place.

It is truly amazing what is being done today with advanced cutting tools and tool paths.

[cadcam]

Mastercam has had this option in pocketing for years to there are the option to use this in many of the Mastercams 2D and even in the 3D paths.

[camtd]

I was thinking about this style - http://www.volumill.com/

The trochordial seems to have alot of excess movement.

Would the volumill style make the trochordial style obsolete?