How do I speed up the "up and down" movement of bit?

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Vectric Craftsman
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Model of CNC Machine: ShapeOko 2

How do I speed up the "up and down" movement of bit?

Post by kristenanne77 »

I have a plunge rate of 30 in/min and the rapid clearence gap set to .2 inch.

Two things I notice is that between "pecking movements" which slow down the job dramatically:
1. the bit goes a bit higher than .2 inch. I would estimate about 1/3 of an inch.
2. it "pecks" into the wood at a very slow rate. Should I increase the plunge rate from 30 in/min to about 100 in/min?

Consequently a job that should take about 25 minutes runs near 2 1/2 hours.

(running a ShapeOko 2 with grbl 0.9 , g code output set to inches)

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Re: How do I speed up the "up and down" movement of bit?

Post by Adrian »

The plunge rate is what controls the movement of the Z axis so if you're find it too slow then it's that you need to increase. Make sure that you don't go too fast for the times when the bit plunges into uncut material and is surrounded.

There is a lot of Z movements in these types of jobs so it's best to keep the rapid clearance as low as you possibly can.

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Re: How do I speed up the "up and down" movement of bit?

Post by Xxray »

Hard to see of any settings you could tweak that would cut a 2.5 hr job to 25 minutes with the same quality, but sure, increasing plunge rate and reducing rapid clearance will speed things up.

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Re: How do I speed up the "up and down" movement of bit?

Post by scottp55 »

Not sure what material or what size holes you're using, but have you looked into doing a "Profile cut/Inside line/Spiral Ramp" ?
I only do hardwoods for the most part, but almost Never peck drill anymore.
Any centercutting endmill(and many others capable of plunging) 50-90% Diameter of the hole can do the Profile cut faster. You need to Accurately measure the cutter diameter and you'll find you have to change Z-Move Speed rather than X,Y Move Speed to control cutter temp as X,Y can Never get up to speed in small diameters and can vary from one diameter hole to the next, But WAY faster AND more accurate/adjustable using tool offset than Hoping your cutter is nominal Diameter.
You probably already thought of this, but thought it might help.
Done thousands of holes this way for over a year after doing dozens of test cut.
Have to play with feeds/speeds these were just Maple defaults for my bits/spindle.
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