Peck Drilling Problem.

[Dougal]

I'm still cutting my teeth on Mach3 and I'm having problems with peck drilling.

I'm trying to use the following command in the MDI.
G83 R5 Z-10 Q0.1 F200

The z axis just hops up and down. Do I have a syntax problem? I'm working in metric (millimetres).

[tobyaxis]

You may want to change your "Q" value from Q.1 to Q1. The machine is hopping because that value is short and being 5mm above the work surface it will take forever to the final Z- value.

[Dougal]

Thanks Toby, but I found chaning the Q value to negative worked.

I read somewhere else that the Q value is the fraction of the hole per peck (e.g. 0.1 means 10 pecks), but a value of 0.05 on a 10mm deep hole only gives me 10 pecks (air cutting because it's cheaper).

Can you offer any insight on that?

[ger21]

Q is the distance of the peck. Here's what the manual says.

This cycle takes a Q number which represents a "delta" increment along the Z-axis.

The manual also says a negative Q will give an error. However, it works for me with Q being + or -, so I suspect the manual is just outdated.

I work in inches, but if I have a Z of -1, and a Q of .25, I get 4 pecks.

What version of Mach3 are you using.

[Karl_T]

On all the CNC's I've seen, the Q value is the feed distance per peck. That is .1 is .1 mm per peck - WAY to small. a Q of 1 is 1 mm per peck - about right unless you got really small diameter drills. I've never tried a negative Q

Karl

[Dougal]

The mystery deepens.

I'm still using the free trial of mach 3 which i downloaded maybe 2 months ago. I haven't yet decided which software bundle will suit best. But I'm leaning towards mach3/cambam/cutviewer.

With Q set to 0.05 I get 20 pecks if I set the z value to 25mm below the retract plane. That fits with it being a fraction (1/0.05=20). But with a drilling depth of 10mm it only takes 10 pecks.

[ger21]

Can you post complete code for a single hole? (all the lines of code you're using)

I have the demo installed on this PC as well, and it works fine here.

[Dougal]

Originally Posted by ger21 Can you post complete code for a single hole? (all the lines of code you're using) I have the demo installed on this PC as well, and it works fine here.

I was typing in the MDI, so unfortunately there's no saved code to post up.
But the next time I try I'll note down exactly what I enter and how it responds.