Sacrafical material

[Todd Mann from Fastech]

We are making a part that takes a piece of alum. 6" x 12" x 144" at a cost of $15,000.00 Our company is only buying one piece. So don't mess up. I know this has been desucced before but i could not find it. What would be something cheep and easy to work with to prove out our programs before running it on the good part?

[Bruce Caulley]

cibatool. It is a pattern making material. We use it to prove large aluminium parts similar size.

 

Bruce

[mman10]

Not sure of the name but there is a blue wax material that you can get. Not sure if you can get it in that length though. If not, how about ABS?

[mman10]

Scratch that, mman not thinking about a 12 foot long piece!

[Todd Tracey from Fastech]

Hey Todd, Freeman Supply has a lot of different types of Prototyping materials available. Plastic wood kind of stuff that is pretty stable.

[G Caputo]

I have a quick question that is bugging me so I'll just go ahead and ask. If you quote one part, but are scared to cut the actual material, aren't you technically making two parts for the price of one? If the job was quoted high enough to do this I still can't understand doing it. That is pure profit being wasted on a non value added activity. I do not mean this to be rude in any way, so please don't take it wrong, I am seriously asking because I just don't get it.

[spade117]

I'm with you greg.

[Guest]

Agree with you Greg,

 

If you're going to quote a part like that, it had better be one you have already done previously and proven a process for it or you better quote it high enough to either do 2 or take the time to make sure it's right before you ever cut.

[betts]

$16 a pound sounds kinda steep, must be a special alloy aluminum.

 

If you aren't 100% sure, cutting some machining wax or renwood to prove out the prg seems to make sense. With the right tools, roughing passes can be minimized or eliminated, and feed rates increased to git-r-done quick.

 

You would have to glue pieces of renwood together to get the length, but it glues well and would work fine.

[Saultspics]

We do some prototype work with MDF.

 

Greg,

We run a simple test if we are worried about the fit of a part. We will rough one cavity in MDF. Then check if the part will fit if so we will machine the mold out of aluminum.

 

ssaults

[Surface]

Not to hi-jack this thread, but I was recently watching a television program, which was showing some aircraft machining. They claim one part was in the machine for a ridiculous amount of time. Something like 6 months.

Accidents happen. I was curious if there were some type of insurance that would cover this type of thing.

[Todd Mann from Fastech]

Ok thanks for all your input. As for the question about quoting and making two pieces. This part is not avalable though boeing and would cost us $27,000 with a 12 week wait. Even with the material costing 15 grand we can still make it cheeper i we have no mistakes. We have a airplane that will drop dead in march so we need to git-r-done. We are not after speed we want acuracy. One shot. I did not take afence to the question I understand exactly what you are saying. But management will only buy one piece. But the kicker to this is the if this one works then they want use to make and opposite for another aircraft. So go figure.

[Greg VN]

I sometimes use styrafoam to test a program.

We have a 5 axis cnc and the programer that programs some of the parts lives in Utah, we are in Texas. I have foam on the cnc right now for a part that is different than we usually do. Foam is cheap and if there are any surprises it will not damage the cutters. It is availabe in several densities. I buy it in 4' x 8' sheets and they will make it in whatever thickness that you want.

[Greg VN]

I forgot to mention that you can use spray adhesive to put pieces of styrafoam together to make it what ever size that you want.

Good Luck.

[robk]

IMO,You need to work with what you have, which is one piece of material. Check twice (or more) and cut once. I can't even see us dry-running a program never mind to machine it twice...

I don't mean to sound cocky, but if we were to do that in here, then we would have been out of business years ago.

[?Mark]

quote:

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I don't mean to sound cocky, but if we were to do that in here, then we would have been out of business years ago.

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+1

NC verification software sure comes handy though

[betts]

No offense, but it does sound pretty cocky. As long as you have humans involved in the process, there will be errors. You can trade some of that check and re-check time for cut time on styro or renwood or whatever. I'm not saying do everything twice, but hedge your bets. I can think of a hundred instances over the years where either a spare saved the job due date, or a practice cut save a piece that would have to be remade. Granted it depends on what type of work you do, and in what materials, but sometimes it is warranted.

Why do you think things are prototyped? Because the first item doesn't always work like its designed is one reason. If you live in a world of very similar parts and pieces, it may seem silly. But sometimes it isn't. If I have a mold that needs 20 1/4" ejector pins, I don't order 20 pins, because the speed of delivery can't wait for more pins to come if one gets scrapped.

[G Caputo]

quote:

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We run a simple test if we are worried about the fit of a part. We will rough one cavity in MDF. Then check if the part will fit if so we will machine the mold out of aluminum.

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I personally think this is the engineers responsibility. Our engineers design entire mandrels that go together without problems, not all the time, but most of the time. They can see what has interference and clearance on the assembly drawings they make.

 

The reason I asked the question to begin with is right now I am listening to a mill, roughing the he$$ out of 17,000 pound piece of 4340 forged steel that I programmed. When it's done it will weigh in the vicinity of 8,000 pounds and I definiteley could not see them making this part out of another material to prove out my program. They pay me to make a program, and that is what is expected of me.

 

The topic just got me thinking is all and I respect everyone's opinion and insight to help me from having "tunnel vision" on how "this is the way we do things". When you know how you do it, it sometimes hard to see that there are actually other ways to do things.

[spade117]

quote:

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Greg Caputo

Aeromet Industries

25 days and counting.....

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what is that about? I thought it said 40 days and counting earlier today.

[G Caputo]

quote:

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what is that about? I thought it said 40 days and counting earlier today.

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Spade,

It did, I'm not real quick on updating my profile everyday. I'm not real computer literate either because I bet there is some way to make it update itself. And the answer to your question. That's when the DAYTONA 500 is. WOOHOO!!!

[within a thou]

Can you not cut the part stock safe then reference the actual material left on the piece to the values set in mcam then comp as needed?

[Bruce Caulley]

It is pretty standard in large aerospace parts to prove in a different material. With up to 5 people spending weeks on the manufacturing and control plan, a couple of weeks of programming in some cases, $15k - $20k pieces of specific alloy with a 3-4 month leadtime on delivery, thin walls, 5 axis swarfing car wreck style geometry, and very specific inspection procedures involved, no-one in their right mind would just shut the door on a 1 off and press go. Vericut or not. And yes, the customer does pay for it, and they are more than happy to.

 

Bruce

[Saultspics]

Greg,

We do thermoformed molds for in house running.

We get a part (with out prints) that the customer needs to put in a tray or clamshell. If the part is complicated we do a test fit in MDF before we machine the mold.