Speed up cutting time without losing quality?

Software
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Hey Guys

I’m just learning Meshcam before my Nomad arrives in December…

I’ve just done a test tool path using the parameters set out in Apollos Flip Frame tutorial, but it said it would take 67.6 minutes to cut per side.

Any ideas how I could speed this up?

Thanks Tim

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I would say remove rought strategy

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Your step over for the roughing is much too small. You can go up to 70, 80 or even 90% of the bit size for the step over - so .1" ish step over.

Also, you can speed up the feed and speeds for the roughing, assuming it’s hardwood. 50 to 60ipm feed would be fine.

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thanks guys I don’t know what I’m doing yet :slight_smile: lol

Thanks Anton42 and Darren got it down to 22.4 minutes changing the roughing, feed and speed rates :smiley:

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I’d point out that there are advantages and disadvantage to climb vs conventional milling, and also there are cases where going too slow or conservatively is actually worse for the work-piece and tooling than cutting too aggressively. Therefore I’ll recommend the following CNCcookbook articles:

Climb Milling vs Conventional Milling & 10 Tips for CNC Router Aluminum Cutting Success, which has some good general guidelines that apply to other materials as well.

-Jonathan

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Thanks Jonathan, will look at them now. On the plus side my flip frame arrived from the USA today!

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In general I’d advise against more than a 50-60% stepover where roughing is needed. Depending on the geometry, MeshCAM might leave unmachined “pillars” where there is too little overlap on the roughing passes. That is more a concern in enclosed pockets, rather than the “open” geometry here. Just a heads-up.

Randy

2 Likes
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Good point Randy. With a ball cutter you need to lower the step over. I should have clarified - if you are using a flat cutter, you can use a high step over value

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The thing which I would really like to see is a physics-modeling G-code post-processor (or better still a CAM tool) which would actually calculate the speed at which the spindle was moving at a given point, the endmill’s rotation, and how much material was being cut, how Grbl was accelerating / decelerating the machine at that point and adjust the feedrate and/or spindle speed in the G-code for optimal chip size.

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Reading a bit more, it seems that HSM (HIgh Speed Machining) is the front-runner for this sort of thing:

http://www.cnccookbook.com/CCCNCMillFeedsSpeedsHighSpeedMachining.htm

Anyone have a list of CAM tools which generate such paths?

Any hope of MeshCAM or Carbide Create being able to do it?

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BobCAD-CAM does HSM. Their 3 and 5 axis packages do a fine job.

I use BobCAD-CAM 5 Axis Mill Pro so I can speak from experience.

BobCAD-CAM is known to bargain and have sales. Push them hard enough and one can get quite a deal. Even with a fantastic deal they are bit pricey…

mark

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@Darren, you are right, that in parallel ball-end finishing if you want a reasonably smooth surface you should set a stepover of 1/8-1/10 the cutter diameter to minimize the “cusping” (extensive discussions of this over on the MeshCAM forum). But this is a separate effect. See http://grzforum.com/viewtopic.php?f=3&t=15531 for a photo of the “pillars” left by the too-large-roughing-stepover effect.

Randy

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Darren I will be using ball cutters