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Center punching before cutting

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acourtjester
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Center punching before cutting

Post by acourtjester » Wed Apr 03, 2019 11:16 am

Here is a trick I use for putting center punch marks on parts I am cutting. When I do a drawing in the CAD and I want to have a center punch mark I locate a circle and give it a diameter of 0.001”. In SheetCam when planning my cutting operations, I make a separate layer for all the center punches for each part as I load them into the plan. I use the “no offset” function and select a tool I call plasma dimple. I use the name of the layer I choose in the layer and the “dimple tool” in tool and do not have any lead in/outs.
I do all the planning for the parts that have center punches and in that last plan after the dimple section. I put a code snippet called “table pause” as the next step. Then continue on with the rest of that cut plan, and any other parts that are in the total cut operation.
The way SheetCam works is it will do all the “no offset” operations for all of the planned center punched parts first and stop. At this point I can increase the plasma amps and hit cycle start again and all through cuts are made from start to end of the cut plan. The thinnest metal I have used this on is 3/16” and attached is an image of what it looks like, it appears deeper than it is. :D
Here is a web address for the Google drive to watch a video.
https://drive.google.com/open?id=1-itiR ... I_y-FX8TKe
DSCN3570.JPG
dimple tool.JPG
dimple tool.JPG (38.53 KiB) Viewed 208 times
dimple 2.JPG
dimple 2.JPG (56.42 KiB) Viewed 208 times
dimple 3.JPG
dimple 3.JPG (20.41 KiB) Viewed 208 times
DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

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SegoMan DeSigns
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Re: Center punching before cutting

Post by SegoMan DeSigns » Wed Apr 03, 2019 11:47 am

Good write up!

I have space allotted on my gantry build for both an air scribe & drill for bend marks and small holes.

Have you seen these units? Do a quick mount and remove when not needed, you can install a tapping head if desired:

http://www.blackalloy.com/index.htm

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acourtjester
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Re: Center punching before cutting

Post by acourtjester » Wed Apr 03, 2019 3:32 pm

Nice looking tool I'm sure well worth it for a commercial operation, I'm cheap and like to finger things out myself :lol:
DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

beefy
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Re: Center punching before cutting

Post by beefy » Thu Apr 04, 2019 12:07 am

Acourtjester,

have you deliberately put a delay after the fire. I got heavily involved in hole centre marking a few short years ago when I was using Mach3. I ended up actually making a microcontroller circuit board with closed loop control of the TorchOn timing, and monitoring of the cut current ramp up.

Reason was I could not get short enough timing and also consistent timing from Mach3 alone. I wanted the shortest possilbe Torch On time to give the smallest crater (centre punch mark :) ) I could get, so that I had great accuracy of marking.

In your video the Torch On time looks quite long so I was wondering if you have actually put a delay in your code. You should be able to get a shorter Torch on time to give you a smaller, rounder, more accurate, "centre punch" mark.

Keith.
8 x 5 water table
Powermax 1250 with Duramax torch
UCCNC controller, UC400-ETH & UC300-ETH motion controllers.
Sheetcam
Geomagic Design 3D solid modelling
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acourtjester
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Re: Center punching before cutting

Post by acourtjester » Wed Apr 10, 2019 8:30 pm

I use only 20 amps for the center punching and have a starter mark (first punch is longer) outside of the ones I want to use. The pierce and cut are the same height, a zero second delay in the tool listing ( no G4 in the G-code). It may not be a short as yours that you posted back then, but its fine for me. I did use it to setup a template for marking the holes for linear slide bearings in 14 Ga. steel and it worked out perfect, very small holes in the pattern for each bearing mount.
DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

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