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I've been considering getting a loan to start a small business involved with aftermarket body parts. As I lay down the plans to do so I have caught a snag. I know that parts that are mass produced are made out of a mold. But what is the mold made of? Metal? How would I get that mold made? Take a prototype to whatever company does molds I suppose. If anyone knows then let me know because I'm really considering running a little business out of my garage for enthusiasts such as those on our forum.
im no expert but most molds are made out of metal.. parts such as polyeurathane body kits or what ever are poured into the mold. this might be possible with fiberglass as well. but as far as getting a mold made, that is probably a specialty product that would cost alot to get made. im sure if you drew a design that someone could enter it into a CNC machine and have them drill it out of a big cast of metal (iron, aluminum, and the such) - granted it would be heavy and large. good luck though, keep us posted
There are a variety of ways of making molds, depending on the quality of parts you want and the manufacturing process. I have a bit of experience with laid-up parts, none with injected parts. You can sculpt masters out of blue styrofoam and styling clay directly on your car, Di-noc the surface or spray mold-release on it and lay up molds out of whatever resin you'd like to use, fiberglass (chopped-strand mat, fine-weave fabric and a coarser fabric) and some reinforcements. This will get you a very limited number of parts out of the mold before it is unsuable. More time, money, weight and material is required to make more durable molds. Way up on the other end of things, you can make really good molds out of Rennshape that's been CNCed from math data, but this costs lots of money, well into five figures for larger molds. Just a few things off the top of my head.
^second that
You can find a book at borders that has this stuff covered for the do it yourselfer for 20$ it's in the car section. There was good info on all the compsites. It had a do it yourself injection molds set up also.
For FG I used plaster of paris/triple expanding spray foam/ bondo and polester primer to make molds, it's ghetto but works well. The glass bumper I made was strong enough to jack the car up with, but it was THICK
Fundamentals of Composites Manufacturing by Brent Strong (published by SME) will give you a good primer on working with composites, if not exactly for the kind of mold info you asked about.
Pardon my spelling, Machinists can't spell much, we just crunch metal...
Molds are very tricky pieces of machinery. But they're all essentiall the same. A typical mold consists of a top half and a bottom half. The top half of the mold sepeartes from the bottom half so parts can be removed from the mold once they're molded.
If its stuff like spoilers you would need a blow mold. A blow mold as the name dictates is essentally a mold that molds parts by first putting liquid molten plastic into it. Then a PRECISELY metered amount of air is blown into the mold. If you blow the air in too soon while the plastic is still fairly liquid, all you get is a part with globs of plastic at various places and parts of the part where theres SUPPOSE to be plastic would be nothing but air.
If you blow air in too LATE, the plastic might have started solidify already and you part might not end up the way you would want it to look like (imagine a midget spoiler)
The idea is to have the molten plastic being blown into very intricate parts of the mold. The thickness of the plastic of the finish part must be within spec, the air content within the plastic must be within spec also. Mold designers achieve this by putting in various heaters, air nozzles, plastic injectors etc etc.
If its stuff like dashs, side skirts, bumpers then you need an injection mold. An injection mold on the other hand is just essentially a mold with plastic injected into it. When it cools and hardens the mold sepeartes and the part is removed. Again stuff like the flow of the plastic, how fast it flows, where it goes, how fast it hardens up must all be considered. Mold designers try to achieve all those by putting in different heaters at different places of the mold and such.
A typical spoiler mold (this is VERY GENERAL) costs anywhere between 70 000 to 120 000 bucks. The cost of the mold is not so much in the amount of metal that it has, the amount of pneumatics its got, or stuff like the accessories its got. Believe it or not, what makes the mold so expensive is the cost of having the mold polished followed by having the mold machined out.
Most molds are machined out of solid chunks of aluminum, size of the chunk depends on the size and capacity of the molding machine. The tooling thats required to machine out that solid chunk is un-real. Its not so much the tooling cost is more like the cost of having to get someone to "SolidWorks" is out, then having the big enough CNC machine to machine it out that would hold up the the XXX tons that your mold weights (although most of it you're turning to chips). To do up a mold properly you'll need something like a 5-Axis VMC (not your typical ma and pa bridgeport machine shop) with upwards of 20 000 RPM. The RPM is what gives you the finish; the better the finish the less polishing you do. Unfortunately the faster the machine the more it costs.
Then you got to pay some unionized guy 20 - 30 dollars an hour (your cost) to polish the mold. For every hour of machining you put into the mold, expect to put in double the amount for someone to polish, finish, install accessories and etc, etc...
That's why this day and age you see more and more parts of just about everything being made out of plastic, in the old days before CNC all the parts are either stamped out, machined out, or casted. All of which other than stamping costs insane amounts of labour $$$ by today's standards. Once CNC came out, you see more and more stuff out of plastics is because molds are cheaper and cheaper to make and the prod. rate of a molded part is faster than stamp, machine, or cast.
That ends my lecture of the day, sadly thats why most molds are made in China today where they can hire a whole village to chip out the WHOLE mold by hand, polish it by hand, ship it over. In the end they do it in one tenth of the time and half the cost.
my gf father makes fiberglass 32 fords and couple of other things. He uses a mold that is made of main layers of fiberglass with a gel coat on the inside for smoothness. Id assume this is what your thinking of doing if u want to make body kits. you can also get alot of parts out a mold. As long as you take care of it.
On all honesty, if you dont know how these molds are made, you probably shouldnt take out a loan to start a business doing this.
Naysayer
It all depends on the plan. Many entrepreneurs tap into local economies of scale using loans as start up capital. It's hard ass work, but there is definitely an opportunity for capitalization.
I've been considering getting a loan to start a small business involved with aftermarket body parts. As I lay down the plans to do so I have caught a snag. I know that parts that are mass produced are made out of a mold. But what is the mold made of? Metal? How would I get that mold made? Take a prototype to whatever company does molds I suppose. If anyone knows then let me know because I'm really considering running a little business out of my garage for enthusiasts such as those on our forum.
Thanks,
Chris
Interior or exterior molds? Have any concepts molded or drawn out in detail? Who is your target market? How will you price your products and/or service? What are you offering beyond the product or service? Have an income, balance, and cash flow statement projected?
If you're looking to do interior work, you'll need to hook into a company like Ashland Distribution Company- they have the plastics and resins necessary to create such molds. You'll have spend countless sleepless nights, devoted to this type of venture (like most others), and have the passion to keep it going. Good luck!
The molds that you would be reffering to are the kind that usctom had suggested.
You would first need a "positive" the prototype part in question. you then make the mold"a negative" to produce more "positive" parts. You can make molds for limited production form fiberglass to produce more fiberglass parts. The tricky part is that the molds ,dependant of part, will need to made in sections. once *** part has set the mold will have to dissassembled to get the part out. it all depends on how complex the part is and the pracement of parting lines dependant on the draft of the part.
Injection molds are an entirely different animal used more for mass production.
if you want to do it, start with something small and try it. get books and read up on the processes and materials.
I do this all day long at work. I use several diffent CAD softwares that obviously make it alot easier.
