[SOLVED] Machine can't handle cutting

WillAdams
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Re: Machine can't handle cutting

Post by WillAdams » Thu Jan 08, 2015 10:08 pm

Our pleasure. We were all beginners once.

Please review the operating checklist: http://www.shapeoko.com/wiki/index.php/ ... _Checklist
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
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temetvince
Posts: 29
Joined: Sat Oct 25, 2014 6:34 pm

Re: Machine can't handle cutting

Post by temetvince » Fri Jan 09, 2015 5:38 am

Hehe yeah, I suppose I wouldn't have had that issue had I followed that checklist!

This should probably go in a different thread, but I don't want to pollute the forums:
Thanks to you all I was able to complete my cousin's late christmas/wedding gift. It's definitely a little rough (especially because my machine needs to be squared/leveled... the left side is slightly lower than the right).
However, if you notice it's pretty messy with burrs all over it. Am I doing something wrong, or is it perhaps too soft a wood to get nice clean cut edges? It seems like it would be a pain to sand every line on something like this.

Image

PsyKo
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Location: France

Re: Machine can't handle cutting

Post by PsyKo » Fri Jan 09, 2015 9:57 am

Hello,

Glad you manage to have it work. :)
I just wanted to say that this kind of message appear more and more :

"I can't get anything from this machine, so the machine is sh*t" (Yeah I'm deliberately exaggerating)

In general, (not only for Shapeoko), start by asking yourself "Did I do something wrong during use ?" or "Am I using it as it should be used ?". This usually helps a lot.
Also a "Hello" at the beginning of the message would help showing your "not so frustrated tone".

Sorry for this off topic, but I don't like this kind of message.
Anyway, I'm glad that you found the solution...

Edit : Also, can you please add a Solved tag to your message title if the issue is solved ? thanks :)

Regarding the last VCarve issue with the burrs, I also noticed it while machining wood.
First, make sure your endmill is sharp enough.
If so, check your speeds and feeds (don't know the numbers, sorry).
Whit soft woods, I noticed this burrs on almost every engrave I did. They disappear with less "fibrous", dryer or harder woods.

EDIT 2 : Thanks for editing your first post (Hello and Solved tag)
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dave_the_nerd
Posts: 143
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Re: [SOLVED] Machine can't handle cutting

Post by dave_the_nerd » Thu Jan 22, 2015 3:53 am

Regarding the burrs, I get them too. I just face sand it with a handheld orbit sander and the burred edges go away fairly quickly.

I've ordered (but haven't tried yet) some better quality bits, but the two other things I hear are 1) downcut mills instead of upcut, and 2) using a more powerful spindle that spins faster.
Shapeoko 2 # 6651: 500x1000mm, Acme screw and belt drive Z-axis, DW660 w/ IC mount, Arduino/grblShield w/ gCode 0.9g and 3D-printed electronics enclosure.

khauser24
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Joined: Mon Dec 01, 2014 12:41 am

Re: [SOLVED] Machine can't handle cutting

Post by khauser24 » Fri Jan 23, 2015 5:53 pm

dave_the_nerd wrote:I've ordered (but haven't tried yet) some better quality bits, but the two other things I hear are 1) downcut mills instead of upcut, and 2) using a more powerful spindle that spins faster.
My experience is from woodworking. Imagine routing a groove in a sheet of plywood. You can choose between many bits, but lets limit this to a choice between an upcut spiral bit and a downcut spiral bit. Would it surprise you to hear there is no "best choice" without considering additional factors? An upcut spiral bit will produce a very smooth-edged groove, except at the very top. The woodchips are easily removed since the bit moves them away from the board. That helps with uniformity of depth too (I'll explain why in a moment). But when the bit is cutting at the very top it is much more likely to cause splinters. That's a direct cost of the cutter moving from below to above that plane ... it's putting upwards pressure at the top, which causes splinters (more so in some woods vs others). If you are able to cut WITH the grain rather than ACROSS the grain you can greatly reduce this.

In comparison, the downcut spiral will also produce a very smooth-edged groove, including at the top. The downside to this bit is at the bottom, where all the wood chips are being directed. Depending on many factors (how fast you're moving the router or workpiece, kind of wood, grain direction, etc) those chips at the bottom can cause you to lose out on consistent depth of cut. More likely you'll overheat the bit and it'll break. An upcut bit can remove stock faster than a downcut bit. Using the downcut requires more passes, each shallower than what you could do with the upcut bit.

Most woodworkers will want the downcut bit and will work with its limitations because of the cleaner edge it provides. One tactic is for the first pass to be cut with a downcut bit and the rest with the upcut bit. That's a little harder to do with CNC work, especially with machines like ours that make multi-tool work less precise than the very expensive machines.

Another tactic, and an old woodworker's trick, is to run a strip of masking tape along the edge. The masking tape gives just enough extra strength to the wood it covers to prevent the splinter. This is pretty easy to do with CNC as well.

For another point of view (still woodworking): http://www.newwoodworker.com/updowncutbits.html

dave_the_nerd
Posts: 143
Joined: Thu Oct 09, 2014 3:23 pm

Re: [SOLVED] Machine can't handle cutting

Post by dave_the_nerd » Fri Jan 23, 2015 11:27 pm

Interesting, I'll have to try the masking tape thing.
Shapeoko 2 # 6651: 500x1000mm, Acme screw and belt drive Z-axis, DW660 w/ IC mount, Arduino/grblShield w/ gCode 0.9g and 3D-printed electronics enclosure.

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