Plastic Injection: In-house or out-house?

[cambria]

I write this attempting to limit any pre-prejudices. I have the option of bringing in a small electric plastic injection machine, 33 ton, 1 oz shot, about 8 yrs old. It would cost me less than a new proto machine for the lab. With this we would be a rare fish: vertically integrated (we make sensors.) We would continue out-sourcing our big stuff, this could be used for protos, lenses, small parts, high-proprietary parts, etc.

I know just enough to know I dont know much: practicality of an on/off type operation, cleaning!, any real benefits. Someone needs to lean over and slap me silly. Need to decide soon.

 

[dgowans]

If you're not going to be making your own tooling, you can kiss the benefit of protecting the design of high-proprietary parts goodbye.

Do you have anyone in-house that's experienced in injection molding processing? If not, will you be bringing anyone in?

Anyone experienced in tool maintenance?

I'm not trying to be a doomsayer, but these are all valid concerns.

 

[cambria]

We would go with a quick change base and use (perhaps) aluminum tooling for protos or short runs. We have an experienced machinist that would do the proto/quick tooling. Iwas playing with the idea of epoxy tooling for very short runs (eg 5 or 6 pcs). No real worries on the proprietary bit, one just needs to be careful if you have all your parts made offshore.

 

[cambria]

By the way, can someone give an opinion on any problems with an "older" electric injection machine. This would be a '98 or '99.

 

[Pud]

Things to consider:

Skill levels in your company (already mentioned!)

Temperature control for the tools (Heaters/chillers, depending what materials)

Material dryers (depending what materials)

Will you be able to buy materials at the price a trade moulder who may be buying tons of resins can get it at?

Maintenance costs: an all electric machine eight years old was new technology at the time - I would budget in to high repair costs. The technology is much more mature now. (e.g. Would you buy an eight year old PC?)

On/Off - Inj. moulding machines are designed for 24/365 operation, although all electric are better than hydraulic as no oil to warm up at shift starts.

Apart from the above, remember, all the scrap is yours (which you will not pay for normally), IMHO I would not buy an eight year old machine - it is likely (though not impossible) to be virtual scrap.

BTW, do not even consider making lenses of any reasonable quality!! (reasons too many to list!)


Cheers


Harry

 

[cambria]

Thanks Harry - yes lenses are tough, so you have to have a tool maker who uses diamond cutters. We design our own lenses, and have seen interesting renditions. Point well made though. Costs, yes, we buy custom plastics material so the cost is ours anyway. My intent is to use it for development and projects with low numbers. We have an excellent professional staff. But yes, the potential killer is what do you have with an electric injection machine that was neat-o in 1999, perhaps not-so-neat-o in '07. The machine is a Cincinatti Milicron Roboshot, well equipped.

 

[Pud]

Cambria:

Did you?..........


Cheers


Harry

 

[cambria]

I let the opportunity pass. I talked to Cincinatti Milicron, and 7 years has seen a lot of evolution in the electric machines. We did not buy it. Regrets? Yes. If the opportunity cam again I would buy it, and it probably will happen within the year.

thanks for the comments and question.

doug

 

[mjh368]

For me the question would be what are you hoping to get out of these short runs.

actual parts to show customers/sales etc.?
Id just SLA them save the headache and overhead.

If you want the parts for testing of properties ect. and hope to use this to justify production, test feasibility of production, generate production figures.

I would caution as you equipment/process/team/mold would have to be comparable.

Not sure what you were looking for but i don't think 5 or six prototypes that you are concerned about proprietary i don't think it is worth the 100k or whatever plus the uncountable additional cost

 

[mjh368]

not concerned

 

[cambria]

Thank you for the comments. Smaller parts, proprietary, quantities in the 500 to 3000 per year volume. Experimental efforts perhaps at quantities less than 100 as they evolve to the short run level mentioned above. Custom materials, perhaps attempts at special processes. Regular production done outside (except perhaps for the very special stuff)

We have SLAs made of course, thats part of modern biz. The kicker is that transition from SLAs to real tooling, where you may want a field test in-force. Cant do it with SLAs, should not go to final tooling yet.

All the comments are valid. How can one rationalize hardware costs and labor loading to support a small injection operation? Perhaps you cant. American industry is fleeing from the concept of designing and manufacturing its own stuff. The mantra of not being an expert is beat out on the jungle drums daily. What hogwash. Learn it, eat it up. Become the expert. And thats where innovation is born.

Thanks for the comments. I move forward with caution, but the best way to take advantage of an opportunity is to be watching for the opportunity, and thats why this forum is a valuable thing.

doug