Best solution to injection mold this part?

[SRT Mike]

My company manufactures LED tail lights for motorcycles. Until now, we have been making "retrofit" kits that go in an OEM tail light. But we want to be able to do a complete assembly.

Check out these pictures

http://i7.ebayimg.com/01/i/05/8c/8f/8e_1.JPG
http://i19.ebayimg.com/02/i/05/8c/9d/12_1.JPG

The black portion is ABS plastic, and the front is clear acrylic/PMMA. We currently sell these to various distributors, but if we can mold a complete light, we can sell about 5 times what we sell now.

I have a CNC bridgeport and I am very confident in the theory of molding, but I've never tried to make a mold. The problem is we have about 6-7 lights we want to do, but the OEM's change them up every 2-3 years, and so our total quantity would only ever be 1000-2000/yr and probably never more than 5,000-7,000 of any given light.

As I see it, my options are

1) Machine molds myself out of 7075 AL and pick up an injection molding machine to make the parts. I dont so much have a problem doing this but I know there will be a learning curve. On a difficulty scale, how would this part rank to make? I do not need to worry too much about the actual lens design because it uses LEDs and we do most of our optics in the LEDs and their lenses, so the outer lens doesnt need to be perfect. I would probably just do a bunch of "pyramids" on the inside and a glass-smooth surface on the outside

2) Outsource. I know others are paying $2k per mold to get these made in Taiwan/China in Aluminum. I would prefer to keep it in the USA though. Also, I dont know if I can get that price since I dont have contacts and a history of volume - what do you all think?

3) Use one of those short-run/proto shops in the USA. I dont know what the cost would be - probably more than offshore.

4) Team up with someone who can do the molding, and let me do the electronics, sales and distribution, and try to get it done quicker that way. Basically someone who would cover the cost of making the mold (CAD/CAM and labor to make the mold) and I could cover actual materials cost, and I could pay a higher per-part cost until the initial labor costs were "paid off", plus a bit more to sweeten the deal and make it worthwhile to the person doing the molding.


I am hoping to be able to find a way to do option #4, but I have a feeling its gonna be tough to find someone to work with in that fashion, especially considering the number of tire-kickers who always want something for nothing, etc, etc.


Does anyone have any ideas? Based on the pics, what sort of tonnage/shot size machine would I be looking at? The light could be held in your hand - its smaller than a car tail light by a little. Is acrylic and abs tough materials to mold? I have a CMM so I can mount up the light and generate a step or igs file, but I am not knowledgeable about where to place runners, vents, and anything about actually running a mold.

ANY insight is greatly apprecaited!

Thanks,
Mike

[ckirchen]

Mike,

My dayjob is plastic part and injection mold design (CNC is my hobby). Many of our customers manufacture molds through us, so we have been involved in all four options at one time or another:

#1. I just finished a mold and am in the middle of making another one. My machine is a lowly converted mill/drill, so your BP should do just fine. If you create a complete CAD model first, the machining will be a large, but straightforward task. If your design is not thorough or if you start machining before the design is complete (believe me, people do it...), the task will be daunting and you will likely be forced to make compromises (i.e. there might not be room for waterlines because of where you placed the ejector pin holes).

#2. I am a strong believer that cheap outsourcing is almost never the way to go. Not just from a keep-it-in-North-America standpoint (I'm in Canada), but from my experience, a cheap outsourced mold is never cheaper than a mold built in NA in the long run. Also, important items are often substandard or missing (such as waterlines, the locating ring, air vents, wearplates on slides, etc.). That means the mold would require repairs before you can even make the first shot. Granted, we have a couple of customers that plan on having to make immediate repairs, so for them, cheap outsourcing works.

#3. By short-run/proto, I assume you mean epoxy molds. Aluminum molds can also be considered proto, but you already mentioned them in #1. Epoxy molds are good for short runs only (because they deteriorate as the parts are made), but 5K to 7K is not a short run. With some types of epoxy molds you might get 1K parts, but you probably don't want to make a new mold every year.

#4. Contact any plastic injection shops that are affiliated with or have their own machine shops. Often you can negotiate a 'free mold' if you agree to purchase a guaranteed quantity of parts.

Without knowing part volume, size (3" x 3"?), or wall thickness, my best guess would be that a machine in the 75T to 100T range would probably be right.

ABS and acrylic are not tough to mold. Any injection shop should be able to run them.

Take a look at this thread: http://cnczone.com/forums/showthread.php?t=8239. It's one from a while back and it should answer some of the questions you have.

Chris Kirchen

[ViperTX]

Whoa....."cheap outsourced molds are not the way to go"......well geesch....15 years ago the company I worked for was getting their molds done in Italy....high quality molds and about 25 % of US made molds.....

There is soft tooling and hard tooling when considering molds.....

If you want a competitive solution send me your drawings....and if you're serious....all you have to do is agree to is a certain number of parts....the cost of the mold is amortized into the parts....but alas before I expend time and energy be ready to deal!

[cpmfastools]

We recently invested in a direct to metal laser sintering machine specifically to address your concerns. We can make production ready tooling in a mater of days, and you own the tool. Our parent company is Chesapeake Plastics a full service injection molding outfit.

Steven
CPMFastools