Raster angle

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performancenut
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Raster angle

Post by performancenut »

Attached is the piece I made today. I had to play with settings before I finally came up with this (I'm a newb so there is a learning curve).

The software calculation time was way off, it was almost double in real life. So I'd like to see if I can trim that down some without compromising quality. First thing I notice is that raster angle defaulted to 45* when I made this. It seems that a majority of this would benefit from a cut going parallel to the long axis (up and down in this pic). This trims off about 6 minutes in the software.

General consensus was that I could probably increase feed rate. Software says it will decrease time but I'm wondering how that translates to reality. Any input on this?

Lastly, this took three cuts to do: rough cut with a 1/2", finishing cut with a 1/8" ball end, and finishing cut with a 1/8" square end (in that order). Software shows 1/8" square will look very rough and 1/8" ball has rounded edges that don't quite do it for me. Thoughts on this?

Any other pointers would be great. Thank you.
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WP_001007.jpg

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Adrian
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Re: Raster angle

Post by Adrian »

As you're only cutting foam you should be able to push the machine pretty hard without losing quality. The actual speed depends on your machine so it's hard to give advice. 3D work is usually constrained by the speed of the Z axis and the many short moves so the machine rarely gets anywhere near the feed rate it's set to in the software. I can't remember if Cut3D has it but VCarve and Aspire have a scale factor setting that allows you to compensate for that in the simulated timings.

The other way to speed it up is to increase the stepover but going by your comments on the finish with the ball end it would sound like you have that too high already. 8% or so usually leaves a good finish.

tmerrill
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Re: Raster angle

Post by tmerrill »

Denis,

Adrian is correct and Cut3D does have an estimated time that must be adjusted for your machine and the type of projects that you do. Even with a good adjustment, it will always be an estimate but it does help see what effect different changes in the toolpath setup will produce.

First, you need to set the Rapid Rate to match what you have in your ShopBot control software. Be sure to use the correct units which are inch/sec in the control panel.

Now, since you have run one good 3D file, open the .LOG file that ShopBot creates for each toolpath run (the file should be in the same directory as the .sbp file) and you can get an accurate run time for that toolpath. Note this time and re-open the Cut3D project and adjust the scale factor until the estimated time for that toolpath comes close to the actual time from the LOG file. Just one decimal place is fine in my opinion.

Do this a couple of times for different files and you should start to have a pretty good estimate for any similar project with roughly the same amount of Z detail.

Tim

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performancenut
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Re: Raster angle

Post by performancenut »

Pardon my ignorance but which scale factor are you referring to?

tmerrill
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Re: Raster angle

Post by tmerrill »

See attached
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Cut3D Est time.JPG

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performancenut
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Re: Raster angle

Post by performancenut »

Thank you. The new times are way more accurate now. Was a little bit longer than reality but I rather a little long than way too short.

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