Any idea on how to prototype, and make small production runs of UV stable plastics?

[dbhost]

I have an idea for an item that is automotive / marine related that I believe there may be a market for, and would like to learn how to prototype a design / build the molds and perform small production runs of a UV stable plastic component. (Think the same stuff used in plastic automobile side cladding and fender flares).

Can anyone here direct me to some howto information on getting this process running? In some preliminary market research, I know I can sell at least 20 units of these things at between $100.00 / $150.00 a pop to people I know personally that are trying to get this type of item (something similar was on the market, in very small runs, and has since gone off market). I can easily envision through simple social media marketing, and word of mouth that this could end up being a reasonable seller of at least 1K units a year.

Any help you could give me pointing me to information on how to get this started would really get me moving in the right direction. Thanks!

[chopnhack]

Could a fabber be the right tool in this case? One can always find a use for a 3d printer ;-) GL

[dbhost]

Hmmm. 3D printing is a bit more sophisticated than I had in mind. Not to mention the size limits, and cost factors involved...

The item I am thinking about isn't exactly complex, but it is a bit on the big side. 12" x say 60" x 1/8" at most...

The thought for prototyping came to me for an excuse to build a CNC router, but production runs on a CNC would be time consuming.

In concept, and I might be all wet with this, is..

#1. Build the prototype, basically just a positive to build the mold from.
#2. Build said mold in 2 pieces with X number of locations to inject resin etc... into the mold.
#3. Resin / plastic. Still doing research. Finding some interesting hits on UV stabilizing and tinting plastics sourced from recycled material. Specifically grocery type plastic sacks. My city has to pay to have plastic bags hauled away to be recycled. I could potentially work an arrangement with city managers to supply sufficient quantities of bags to be recycled as long as I can get the production issues worked out and end up with a quality product... I would have to make sure that whatever process I use would be environmentally acceptable, and safe...

[LCHIEN]

what are UV resistant pastics, I ask myself...

Oh, Look it up on google....

http://www.plasticmentor.com/97/whic...are-uv-stable/

Just how long to you is stable??? And that of course is a subjective question because you cannot just pick a date like 5 years and in 2018 it will be perfect and in 2019 it will disintegrate. More like a exponential decay of properties vs. time - fading, strength, brittleness/flexibility, chalking etc.

And, are you talking forming, machining, welding/gluing or injection molding? Some of those are not low-budget short run techniques.
Your best bet is to find a reputable local plastics manufacturer with a spectrum of services and talk to him about your application, material choice and budget.

[LCHIEN]

ha, you posted while I was composing my answer.

if planning on depending upon recycled grocery bags make sure you don't get totally destroyed when you local government outlaws single-use plastic bags as many municipalities are doing (Austin for example).

you're talking a big item, outdoors I presume, does it have to be well finished or rough-looking is OK? YOu mentioned molds - High pressure, high quality injection molds can be very expensive. Virgin plastic vs. recycled plastic - the recycled stuff probably won't look as nice and you may have trouble controlling its properties as well, if stability is important - grocery bags are actually designed to be UV unstable so they break down outdoors.

[woodturner]

would like to learn how to prototype a design / build the molds and perform small production runs of a UV stable plastic component. (Think the same stuff used in plastic automobile side cladding and fender flares).

If you are thinking production molds for an injection or blow molding machine, they are VERY expensive - six figures at least, even a small mold is $50K or more.

Could you use a wood form and fiberglass, then coat with a layer of the UV stable plastic?

Can anyone here direct me to some howto information on getting this process running?

I know a lot of folks and faculty in that area. Probably would be willing to give some free advice, might be able to get some help as a student project at pretty low cost. PM me if interested.

I can easily envision through simple social media marketing, and word of mouth that this could end up being a reasonable seller of at least 1K units a year.

You won't want to do a production mold for small quantities - those 100K molds are used to produce thousands a day, such as milk bottles.

[woodturner]

Hmmm. 3D printing is a bit more sophisticated than I had in mind. Not to mention the size limits, and cost factors involved...

Prices are dropping rapidly for 3D printing. Small printers are in the $200 range. There is also an older technology, SLA, which builds up the project by hardening liquid resin with a laser. My students just got back from MakerFaire and tell me SLA machines were available for a few hundred dollars at the show.

I'd think seriously about using an easy to fab material for the base, maybe fabbing it in sections to fit a smaller 3D printer, then assembling them and coating the unit with either a UV inhibiting plastic or just painting it.

#1. Build the prototype, basically just a positive to build the mold from.
#2. Build said mold in 2 pieces with X number of locations to inject resin etc... into the mold.

If you can find a low temperature melting plastic or a catalyzing plastic, you could make a wood mold with a cavity about 1/2" larger than the piece. Make a prototype piece, finish it so the surface is smooth, coat with mold release, then coat with silicone rubber and push into the wooden mold frame. This will make a silicone rubber mold, but such a mold will not withstand high temperatures. This technique is used a lot for model making and in the special effects industry, so you should be able to find a lot of books and information on the web to learn the details of how to do it.

[Stytooner]

The size of the item will help determine the cost. Yours is very large really for a plastic item. That means big money to get setup no matter what technology you use.

As mentioned, any injection molds will be extremely expensive to start up. I have made a few of my own molds here for small parts that I thermoform and even then just the material was a few hundred dollars alone. I used material called Fortal aluminum, which is in the 7000 series.

Hand pouring resin into several holes will also not give very good results and will be prone to a lot of waste or repair needs. No way to know until you open the mold. It would not be as consistent as injection molding.
This is one of the reasons why injection molding is far superior. Another is shear volume capability with IM.

I think any sort of resin used at that size part will also be more costly than you think. Probably very close to your selling price target.
If I were going to do it, i'd skip plastics altogether.
I'd start out with a known low cost material that can easily be manipulated and is used widely in the Automotive industry. That is fiberglass.

It has a reasonably low start up cost. It can easily be manipulated, strengthened and finished with consistent results. I would not consider any other method for something the size you are considering.


PS: There may be local shops that specialize in fiberglass already. They may be willing to do the work and you simply do the warehousing and selling.
No need for you to even invest in a respirator. Worth checking into I think.

[Tom Slick]

Could the part be thermoformed? It's realitively simple and not very expensive to have a shop do it for you. Your mold is easily modifiable to make design changes.

[dbhost]

Could the part be thermoformed? It's realitively simple and not very expensive to have a shop do it for you. Your mold is easily modifiable to make design changes.

Okay, toss the recycling idea out the door. I was trying to figure out a way to make the product more "Environmentally responsible" and thus marketable. However the target purchaser of this particular product aren't exactly the Woodstock type, and thus most likely wouldn't see that as a selling point anyway.

Looking into the types of material used for this sort of application, ABS plastic is quite frequently used.

I suspect that thermoforming could be used, but the component is rather large. I would suspect that vacuum holes would have to be in the form itself such that the form worked as part of a thermoforming press or whatever the machine is called...

I suspect I need to build a prototype and try it out...

[Slik Geek]

Hard to judge without more details (but understand why you are being vague).

"Do it yourself" injection molding seems to me to be a dead-end for the "hobbyist". You need sophisticated controls, timing and a complex mold to do it properly. (And often high pressures forcing the plastic into place).

Thermoforming, on the other hand, may be done by the amateur so you could prototype that at least, and with some experimentation and effort, maybe you could do that yourself for items you could sell. Assuming, of course, that the complexity of your product isn't significant and lends itself to thermoforming.

First do a sanity check - how big of a sheet (and thickness) plastic would it take to do a thermoform version? How much will that sheet cost? Is there really any profit in there for you to pay for your effort and setup?

Maybe that similar product went off the market because they couldn't make any money!

In your volumes, at least initially, CNC machining may be more practical.