Internal machining. Error messages.

[MAX THE MILLER]

I've been experimenting with internal machining on a Mirac and have produced the attached .LCM file.

When I try to generate Gcode I get the errors below which I do not understand.

(Drilling)
Cannot Process: Drill:8 diam:6.00 is less than current internal diam:11.11
Cannot Process: Drill:4 diam:10.00 is less than current internal diam:11.11

(Internal Roughing)
Cannot Process: Current internal diam:11.11 is less than min. tool diam:12.00

There is no internal diameter of 11.11mm and I don't see how it matters in any case when drilling.

I can understand the Internal Roughing problem as the boring tool is specified as 12mm and in order to start boring it would need to make a cut of 1mm in order to enter a 10mm drilled hole and that's with zero clearance on the back edge of the tool. There's still a reference to an internal diameter of 11.11mm though.

Would appreciate any advice. Thanks, Max.

EDIT. Can't upload .lcm file so renamed as .txt

[Mitch]

Hi Max,

it looks like it must be related to some settings you have made within Quickturn2D Design. i have opened and simulated your drawing without errors on a standard installation of QuickTurn. i suggest you make a fresh install of the software.

did the machine manage to complete the centre drill operation?

Thanks

[MAX THE MILLER]

Thanks for the explanation.

The problem is down to my defining a centre drill as having a major diameter of 7/16", 0.4375" or 11.113mm.

This looks perfectly legitimate to me. QT2DD seems to be working on the major diameter rather than the minor diameter, hence the error.

MAX

[MAX THE MILLER]

I managed to get rid of the drilling errors by fitting a 6mm centre drill in place of the 11.1mm diameter one fitted and editing the tooling file accordingly. I believe Miracs came with 5mm centre drills? I had use a 6mm one as the only spare DB25 holders I have for use with my ATC have 6mm bores.

The error relating to needing a minimum tool diameter of 12mm seems to be explained in this thread:-

https://www.denfordata.com/bb/viewtopic ... ter#p25125

This suggests that the hole needs to be pre-drilled to a minimum diameter of 14mm. This seems odd as my boring tool will easily enter a 12mm hole and is specified as such. It has an 8mm dia shank.

[Mitch]

Hi Max,

Apologies i didn't get back to you on this previously.

you are correct in that QuickTurn 2D will look at the shank of the centre drill when deciding if it can use that tool or not. which is correct but it doesn't help when you're trying to use a smaller drill.

For example if i wanted to use a 2.5mm drill in a Denford lathe, i must set the shank of the centre drill to be less than 2.5 so that this tool will be used but this brings the issue that on the modern Denford machines the shank is 5mm and it will use some of this to cut into the material.
I will look into what can be done to resolve this in a correct manner, ensuring the centre drill with a 2mm tip can be used but without compromising the dimensions by drilling too deep.

looking at the post that you linked to regarding internal profiles, this was flagged to me a couple of months ago and work has been put into QuickTurn 2D Design to resolve this. downloading the latest version will have the fix in that correctly identifies internal and external cuts when importing a DXF file.