ELIMINATING NO-OFFSET HOLES

[enzed]

Please see attached photo. Can someone please tell me, what causes the holes at the start of no-offset cuts, and is it possible to prevent them? I will be very grateful for advice.

enzed

[acourtjester]

Looks like pierce holes, the time is too long. There is a delay in the G-code that helps.
If you list your equipment someone may be able to help you out with them.
You can also search here for posts about this problem.

[exapprentice]

well that's impressive divots at the start of a cut but the end of cut looks really good

I agree with "acourtjester" if that is the start of the cut do you have any pierce delay set?
have a look at this thread http://www.plasmaspider.com/viewtopic.p ... 9&start=25
might be of some help

[james.davis]

Can you post the dxf layout that you cut from? Does it do this on all your cut programs?
Jim

[enzed]

Hi everybody. Firstly, my apologies, I should have given more information: I am using a Powermax45 set at 30A and 111V. Operating software is Mach3. Cutting speed is 2 m/min (about 6.6 feet/min). Other settings are: Pierce delay of 0.2 secs, pause at end of cut 0 secs, pierce height 3.8 mm (0.15"), cut height 1.5 mm (0.06")and plunge rate 500 mm/min (19.7"/min). Material is 1.6 mm (about 16 gauge) mild steel.

And yes Jim, it does this on all the 'no offset' cuts, which are all set with a 0.2 second pause delay, so I suspect that this is the cause, but I may be wrong.
enzed

[WyoGreen]

With that thin of material, I'd try eliminating the Pierce delay and see if that helps reduce the divot.

Steve

[mike 1948]

Just a thought, maybe if you lower your pierce height to around 2.5mm( or something closer to cut height). The cut cone would be smaller at the pierce.

Mike

[littlefatbuddy]

I use a zero pierce delay on 16 gauge. It doesn't completely eliminate it but it helps a lot.

[motoguy]

On 16ga, I pierce and cut at cut height. That may help some as well by removing the dwell time, while it comes down from .15 to .06.

[tcaudle]

Dwell is the length of time from when the torch actually fires and it actually starts moving in XY. So any delays or plunge time adds up to a pierce that widens out looking for more metal to cut Its difficult to get zero divots because its a fine line between leaving no divot and a bad pierce.

To Motoguy: if you pierce and cut at exactly the same height the DTHC will never come on. It uses the Z plunge and the move to cut height to trigger the DTHC ON. That eliminates all of the other variables and happens at the same exact spot each pierce BUT there has to be two different numbers . They don't have to be much (.01") but pierce needs to be slightly above cut height.

[motoguy]

Good point, Tom. I actually pierce. 001 above my cut height.

[enzed]

Hello everybody. As always, I am very grateful for all the advice; thank you very much to all of you who responded to my request for guidance. I am also always very impressed, not only with the depth and diversity of knowledge available on Plasmaspider, but also the willingness of members to share what they know. The spirit of teamwork and support is amazing. Thank you very much guys, and best wishes to you all. enzed.

[lazybear]

Thank you all for answering a question I was also going to ask! Mine so far have been smaller, but was wondering the exact same thing.
Stacey