Thicker plate piercing strategies?

[Eric C]

I have a STV 5x10 table with the optimum controller and a hypertherm 85 smart sync plasma . I’ve fought some of the controls and had to really learn the quirks of their system. What I wanted to know about other brands is how do you tackle piercing holes in thick plate like 3/4”- We make a good deal of baseplates and parts with 13/16” holes. When I pierce with a new consumables, they get ruined in a few holes. Any advice or strategies like pre drilling(not sure how to start on that) would be great. Thanks!!

[djreiswig]

If you're using SheetCam, try using the ramp pierce. I don't do much thick plate, and since I have a 65 I use edge starting when possible.

[Joe Jones]

If you can drill a simple 1/8" hole at a specific point, you can pierce at the edge of the hole and that will be the same as cutting in from any edge.

Joe

[Eric C]

If you're using SheetCam, try using the ramp pierce. I don't do much thick plate, and since I have a 65 I use edge starting when possible.

No sheetcam, my machine came with the optimum software. I don’t know if I can use sheet cam.

[Eric C]

If you can drill a simple 1/8" hole at a specific point, you can pierce at the edge of the hole and that will be the same as cutting in from any edge.

Joe

That’s what I’d like to do- but I don’t know how to accurately line up multiple drilled pilot holes with the start points of the torch.

[Joe Jones]

It is a bit tricky, but it can be done.

Joe

[FabLab]

In my opinion your best bet is to pierce in the center of the hole and use a straight leadin I would experiment with raising my pierce and cut height on the holes as well, but .812 hole in .750 it's going to be tough to get good consumable life.

The other thing I have done in the past is setup a job that just does the piercing, use old consumables for that job, switch to new ones and run a second job that does the cutting..

[weldguy]

Hypertherm chart says your pierce height should be at .250" so first off I would check to be sure that your machine is piercing accurately at that .250" height. Often what you set on the screen and what it actually is out at the table can be different.

If you find that your torch is lower than .250" when piercing adjust your height to get an accurate .250" pierce height and see how that goes.

Let us know if you pierce height was accurate or not and we can go from there.

[SRdesign]

What weldguy said is definitely the best place to start. If you can’t get it figured out with pierce heights you could try an easy scriber https://www.theeasyscriber.com/ or my pen plotter https://overthetopfab.etsy.com/listing/1598577295
You would just have to run the marking operation, drill your holes at all of your pierce points, then run your cutting operation.

[Joe Jones]

Set up a jig to place a SHARPIE pen into it to DRAW the shapes you are going to cut onto the metal plate, using your cnc table as a plotter. Remember to offset the drawing the same distance as that from the pen tip to the torch tip, and offset it on the same axis (X or Y, or Xn + Yn, etc.) In the drawing mark exact pierce points. Now use a mag drill or a hand drill with a slide jig to drill the 1/8" pilot holes at those points.

Joe

[SegoMan DeSigns]

The 105 (Non SYNC) is production pierce rated to 7/8" with a 1.25 second pierce delay time, To pierce 1" I delayed that too 2 seconds with good results. Always allow the thickness of the metal for the leads ins if not more when possible. like other posted the center of smaller circles is best. The wiggle lead in was an expensive experiment and now I use the ramp mode.

A peck pierce will mark the pierce points for drilling purposes, A search of the forum will give you multiple results on how to do it.

[adbuch]

The 105 (Non SYNC) is production pierce rated to 7/8" with a 1.25 second pierce delay time, To pierce 1" I delayed that too 2 seconds with good results. Always allow the thickness of the metal for the leads ins if not more when possible. like other posted the center of smaller circles is best. The wiggle lead in was an expensive experiment and now I use the ramp mode.

A peck pierce will mark the pierce points for drilling purposes, A search of the forum will give you multiple results on how to do it.

[Ironman]

If you can drill a simple 1/8" hole at a specific point, you can pierce at the edge of the hole and that will be the same as cutting in from any edge.

Joe

That’s what I’d like to do- but I don’t know how to accurately line up multiple drilled pilot holes with the start points of the torch.

Run the program without cutting, and pause before starting a cut path. this is your piece point. Test fire the torch at this point and this will create a small dimple at the pierce point. Drill a hole here.

[tcaudle]

No matter what they call it , pretty sure that is a MyPlasma Control and their limited software so it may not be easy to adjust the parameters and order the cuts . Its my understanding that SheetCAM will work to generate code for MyPlasma controllers but that may not be the case. Someone who has done it could possibly chime in and let us know. If you piece a the correct height for the correct times you wont burn out consumables prematurely.

[PlasmaDon]

Has anyone tried water level over the top surface ?

I used to do some simple Plasma programming 38 years ago
as an apprentice at a large shop with a very large machine (IIRC 400 amp), and they ran the water over the top of the plate.

I have run it this way when oxy cutting thick plate on my own machine, but not plasma yet.

[SeanP]

If you can drill a simple 1/8" hole at a specific point, you can pierce at the edge of the hole and that will be the same as cutting in from any edge.

Joe

That’s what I’d like to do- but I don’t know how to accurately line up multiple drilled pilot holes with the start points of the torch.

This is how I do it, it works very well,,,,,unless you miss drilling a hole
I now white mark each pierce point as its on the move which helps to not miss drilling one.
A good quality carbide drill is best 3mm, adding a stop on the drill helps as well to prevent bursting through when drilling.
I just place the circle on centre of pierce point.
I do quite a few plates in 15mm or even 20mm,,,XP45!

Peck pierce.jpg

[BTA Plasma]

You should have the freedom to pierce higher and longer if need be and raise initial cut height to clear the pierce puddle. It is required knowledge for successfully cutting material near pierce capacity.

[cutnweld]

I use plasmaC, you can select pierce only mode and it will go around piercing all the holes with an old consumable set then you swap in a new set for the cutting. Saves new tips. Like a predrill, piercing a hole takes away material then it will not sense an arc ok to release motion. PlasmaC overcomes this by putting in a pierce offset that you can adjust to whatever works for you. Pretty slick actually.