Help me optimize this cut

[whiskeymike]

I'm cutting 2x3" spacers (think big washers) out of 1/4" mild steel. I need several thousand of them. Here's a picture of the spacer..

spacer copy.jpg

Here's a picture of the work for a half sheet...

spacer full sheet.jpg

A half sheet is about 400 parts so that translates to about 800 pierces, and 4400" of cutting because each piece is cut individually with a .33" gutter between each piece.

Can anyone give me any ideas how to reduce the amount of cutting to preserve consumables or shorten cut time? I've thought about making a grid of them without the gutter and trying to make it cut all the holes first, then long lines of 47". Or doing clusters of 16 (or some number). But I'm concerned it's not going to cut across the gaps reliably where it's previously cut. Or that it may warp cutting long lines.

I have complete control over the design, so if I need to get rid of the rounded corners or similar changes, I'm good with that.

I'm also looking into to see if a metal fab company could stamp them out more economically. If anyone's familiar with that process.

[gary42095]

i dont have any real help for you. i would think shear and punch could go much faster but who knows. only thing i could say, .33 in between seems like way too much for waste. thats alot of dross cleanup when your done.

[whiskeymike]

Thanks. I do the .33 so I have enough steel for a .25 lead in to make it clean. I understand that your leadin should be as long as your material is thick. I'll see if I can dial it in a bit. However, I'm hoping there's a method to reduce the pierces and cutting all the way around as that would be a big gain.

I'm going to try a new design like I mentioned. It's just at $180 a sheet, I don't want to burn up too much steel trying stuff out.

[MGardner]

I have a couple of jobs that I do every year that is similar to this. One of them are plates that are 12" by 12" with 4 holes in each plate. I do a "grid" type of cut as you were talking about. I cut all my holes first then cut in sections. I start at the top cutting the first horizontal cut all the way across first then I do my 4 12" vertical cuts (I don't do all 48"x48" cuts because I found that the metal starts warping between cuts and the torch can hit when you start getting towards the bottom of the cuts) then after my 4 12" vertical cuts I make another 48" long horizontal cut then repeat this process until I get all of my 12"x12" plates cut. I also do this for a couple of other plates that I cut several hundred of at a time.
If it helps I can post a picture of what I'm cutting? or I can send you my PCM file that shows the order of the cuts.

[Dugan]

Make them in CAD and add a small piece to link them together in rows, this can easily be cut off or bent off if done right. This will allow one cut to cut half of each object instead of piercing for each. You might just have to finish them up on a grinder.

What you save in consumables youll waste in time tho.

[OTHill]

Can you not do chain cutting? Don,t know what your washers are for but you could also make a double your kerf cut in from the end to the hole and your pierces are down to one per row.

[Stout]

Radiused corners make common line cutting difficult. But it could be done if you put some thought into it. Bridging the pieces together would be fairly simple. If you group the pieces into four, extend the cut line from one to another. Since the outside cuts are clockwise, the group of four could be cut counterclockwise. This would eliminate three pierces in the four parts.

You could effectively string all of the pieces together for longer cuts. It's just more CAD time to avoid the torch traveling over previously cut lines.

Look here.

http://multicam.ca/cnc-plasma-cutting-t ... fficiency/

[whiskeymike]

This is all super helpful guys! This is the kind of stuff that makes this site awesome. The article posted really gives me some ideas of how to loop through these that might really improve what I'm doing. The chain cutting and common line techniques look like what I'm looking for.

Once I get through some trials, I'll let you know how I make out. Thanks again!

[BTA Plasma]

I trained at a customers facility just outside of Dallas Texas. They wanted to optimize a large 8x12 machine to cut almost exactly what you want to cut. We ended up with edge starting every line, taking a 18% loss in quality cut speed the plasma was able to jump existing lines without loosing its cut kerf. Basically cutting strait stripes up then down then up then down then side to side then side to other side. The pieces came off so fast they beat the absolute pants of the shear and we estimated them profiting $873 per hour from that program change. This was 1/4 material with a powermax 85. Since you have to auto home/auto square switches already installed in your Star-Lab you can utilize them to create a XY reference plane by welding on a strip to your water bed and auto homing/auto squaring and cutting right down that path. This will give you the ability to slide your sheets right to the edge of your travels optimizing edge starting capability.

Some things to consider.

[vmax549]

I would cut them from .250 bar stock not sheet.