I’m still alive and kicking, cnc plasma update

JTknives

JTknives

Joined
Jun 11, 2006
Messages
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Just wanted to pop in and let you all know I’m still alive. I have been neck deep in the cnc plasma build. It greatly underestimated the time it would take to build it. Plus my obsessive nature is not helping. But we are really close and as soon as I have time I will update the “WIP” thread.

I also hoped you guys would share alittle info with me. I’m trying to ballpark estate cutting cost. I’m trying to come up with a simple pricing structure. My first thought is go by the inch like most cnc shops. Was thinking of going simple as in total length times 2 plus total width times 2. So if you blade was 10” long and max width was say 1.5” the total cut inches would be 10x2+1.5x2=23”
There would also need to be a per hole charge as pearcing is one big factor in burning up consumables. There would be price breaks if you wanted batches.

So with that all said what do you guys normally pay to have blanked cut?

Thanks guys - JT
 
I have a man with a Waterjet cut out my profiles, Pin holes etc, all I can say is it’s well worth it! ———————I do wish you the best of luck with your build & biz .. let us know when you figure out your costs....
 
When I did this work, I figured about how long consumables last, so it got lumped into an hourly charge. When bidding on a job, you really have to set it up in whatever cut software you're using, nesting all the pieces together with proper lead in & out established. Material type and thickness and expected cut quality will all change how fast or slow it cuts (which is why you can't really do a per-inch charge). That way, you know how long the job will take and can add together machine run time, consumable use and whatever margin you're trying to make.

On piercing, it sucks on a plasma, and will come down to how well you can dial in the tip height. If you have automatic height adjustment, and touch-off capability for pierces, it'll make your life a LOT easier. If you don't, fighting warp will be your new nemesis.... Regardless, since so much of this comes down to your ability, it's hard to justify charging the customer "per pierce".

In your shoes, I would create a reasonable hourly rate + flat setup fee and start cutting stuff, making notes about time, material and consumable usage. Then, after a little experience, you can adjust your rate up or down as needed.
 
Well I know nothing about Plasma cutting, but as an accountant I know all about the finance stuff. Before you can establish a rate, you must know all of your costs that would be associated with a job. Of course all of you direct consumables, but you can't forget about other factors, such as set up and taken down, other tools/equipment needed for the process. If there is speed variables does that affect the rate of consumables used? electricity used? etc. Now obviously the easiest way is to find what rates the competition uses and base it off that but then if you don't know your costs you won't actually know if you are making money are not. Many small businesses think they are making money because cash is coming in but in reality they are losing money on each transaction.
 
I had a guy local to me do a little milling recently and he offered to profile/drill holes/surface blanks for me for $25 each. I forgot what he said he would use to profile but it was on a CNC program and would be very precise.

I never used him though
 
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The table has a floating z axis with a switch as well as ohmic height touch off. Once it starts a cut the THC takes over and it controlls the cut height by measuring the arc voltage and making adjustments to the Z. We get really good consumable life when we use actual hypertherm consumables. We tryied a handful of “knockoff” consumables and no comparison.

My gole is to make it feasible for you guys to get one or two blanks cut and not cost an arm and a leg. Cut speed will be fairly consistent as we will be limiting our selves to around 1/4” and under. This is only until we buy the new larger plasma system next year.

We will also be providing the material and keeping it in stock. So we have to figure out a way to deal with material cost and scrap. From my research on that topic most people calculate it as a square area. What size square is required for the desired profile and charge per square inch for that area.

Thanks guys. - JT
 
Lots of us are eagerly awaiting you getting this rolling. I'm looking forward to having you cut a few AEB-L blanks and heat treat them for me.
 
Don't most CAM programs give a run time estimate? I was under the impression that this was how most job shops calculated these types of things, just converting it into an hourly rate, give or take setup and handling costs. Obviously the hourly rate would factor in consumables and such as well.
 
Yes they can. Plasma cam programs are few and far between. There are a few out there like sheet cam. The issue is trying to incorporate it into an easy formula for our website. That’s why I was trying to come up with a simple way to price each blade. Most likely we will just set a per blade price like how our heat treating is. At least at first till we get a better idea on overall costs. I do need to round up a few people to get started as I’m thinking about ordering AEBL stright from uddaholm. I do have one guy patently waiting on the cnc becaus he wants 30 blades. Looks like we are going to order a handful of .135 AEBL sheets to get started unless others chime in on the thickness thy are wanting. The plan is to surface grind the .135 down to .125 after heat treat.
 
Hey JT,
Just my thought but I think people who want AEB-L will want it to be .10, .09, .07. .125 is what I would use for skinners and hunting knives. Maybe Stacy or other kitchen cutlery makers will chime it.
 
I'm wanting kitchen cutlery thicknesses, slicers and such. .07-.09 thicknesses. Really want some high hardness for that kind of thing, above 62 and I know AEB-L shines for kitchen knives at high hardness.
 
THC = torch height control

It’s a system that monitors plasma arc voltage and adjusts the height of the torch off the steel to keep the voltage constant. As the arc gets longer the voltage goes up. So the THC uses this information to keep perfect spacing between the steel and the tip of the torch. This means that the steel sheet could be crinkled like a ruffles chip and it will keep perfect spacing as it cuts across the surface. Or a more practical application as in bowed sheets.
 
Just need to finish wiring up this nightmare.

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