Before we start contacting casters, we should have all the specifics of the project worked out. What kind of plastic, what colors do we want, what method of casting, what kind of mold, best practices, etc, etc.

I've started a seperate thread for issues of funding, distribution, website sales, etc. So, for now, just materials stuff here. Thanks.

I'll scour the BBS for old info and post it here, but I really don't know much about casting, so I don't know what is accurate and what is not. If you have information about this, then please let us know!

Below are color requests that I was able to find in previous threads. Red is most requested, followed closely by Smoke. Stu was working on Blue, Red, Green, Amber, and Smoke which seemed to provide majority coverage.

"Standard" Colors or Materials from previous threads

• Red (Original, BMW, Audi, VW)
• Green
• Dark Green
• Blue
• Amber
• Bright Yellow Green
• Yellow
• Charcoal Gray (the same color as the fascia)
• Smoke (Smoke in in visible light but matches VFD color when illuminated)
• Milky gray (appear original when unlit)
• Dark gray (black when unlit, smoke when lit)
• Milky White
• VFD teal
  

Specialty Colors or Materials from previous threads

• Silver/Chrome
• Phosphorescent tint (blue and blue green)
• Soft resin or rubber caps
• Edge Lit (2 Part button with opaque material on top and translucent below)
  

The method used to date involved hand casting with a 2 part mold using a liquid silicon or polyurethane rubber. The buttons are cast using a resin. Problems have been encountered with bubbles, color matching, and uncured resin. If this route is used again, a pressure chamber should be used to reduce bubbles. Heat curing may be necessary depending on the resin used. Color matching to lenses will be difficult.

More on the how to of molding and casting can be found on Smooth-On's site

Other methods discussed include Injection Molding. It was found to be cost prohibitive. ($7000 for the mold).

From http://www.matrixenterprises.com/molds.htm, RIM molding sounds like it may be a cheaper option but I have not followed up with them to find out more. Firefox let me know if you wish me to do so.

The types of casters involved have included hobbyists and "cottage" casters that are involved in model making (Casting_Fool and SCModelWorks). Given the lack of success with the latter group, I'd try a more industrial group next.

One important point to make. Casting directly from original buttons may not produce the best light diffusion results. The last interation that Stu went through had the caster modifying the buttons to fill in the empty spaces behind the buttons to reduce bright spots in the middle of the buttons and knob.

Mach, that research is awesome, awesome, and awesome. That'll really help us know what to ask when we call these people.

Thirdly, yes, I also noticed how Stu filled in the blank spots. I can't think of an easy way to have a caster create that mold unless we send them buttons with the blanks filled in (with epoxy or something, carefully tooled to perfection by us).

You can probably get away with caster's wax or sprue wax to fill in the buttons. It can be adjusted as need be and smoothed fairly easily. I'd like to see the buttons that Stu got back to see what the previous caster did.

Here's the original lenses that hade been discussed for color matching. As those lenses are no longer made, I don't know what the demand would be for matching colors.

http://www.riocar.org/lens.php

Got some interesting information today from calling casters during my lunch break at work.

One idea was to machine the buttons from "bar stock" or "rod stock". I doubt it would be possible, considering the fragility of the button shafts, but it's still one to keep tucked in the back of your minds. Might be cost effective for small runs.

Also, I confirmed that injection molding is totally out of the question (well, based on the casters I spoke to). One said it would be between $3,000 and $8,000 for the mold itself. The mold would be made of aluminum or steel, created by robotic machines based on the specs in the CAD, and then would be altered to allow plastic to flow in and for the buttons to be ejected out. Then, it would cost between $200 and $500 to even put the mold into the machine. At which point, they'd push the GO button for like 5 seconds before hitting STOP, because that's all the time it needs to make 300 sets. So, it'd do a quality job, but only if we needed 300,000 sets.

Some more terms, one guy mentioned creating a silicone mold to cast the buttons from. I hadn't heard that before, so it's a good one to ask casters.

For terminology, I was even told to speak to "prototypers" along with casters. Because if our run size is as "small" as 300 sets, that might qualify as prototyping to some people.

I just hope the CAD will help a casting shop create a precise mold, since they don't have the machines that the big injection molders have. We'll see.

Silicone, Poly-urethane or latex is just the material the mold is made from when doing a hand cast. Like saying a piece of furniture is made from pine, walnut, or maple. Each have their benefits and drawbacks. The caster will likely pick the material depending on our requirments for number of casts and resin used. In other words, we shouldn't have to worry about this.

See here for more info: http://www.smooth-on.com/howto1.htm

I confirmed that injection molding is totally out of the question (well, based on the casters I spoke to). One said it would be between $3,000 and $8,000 for the mold itself. The mold would be made of aluminum or steel, created by robotic machines based on the specs in the CAD, and then would be altered to allow plastic to flow in and for the buttons to be ejected out. Then, it would cost between $200 and $500 to even put the mold into the machine. At which point, they'd push the GO button for like 5 seconds before hitting STOP, because that's all the time it needs to make 300 sets. So, it'd do a quality job, but only if we needed 300,000 sets.

Based on the lower of the mold costs injection molding would be doable. Risky, yes. But doable:

Mold $3000.
5 colours setup: 5 x $200 = $1000
Plastic is cheap. Let's assume $500 ($100 per colour) gets us more plastic then we could ever sell.

Now if that gets 300 sets of 5 colours, you'd need to sell 100 sets at $45 to break even. Let's add $5 for sundry costs... $50 for a five colour set anyone? I'm confident that you would sell 100 sets at that price. Anything over 100 sets becomes profit (which might be another hassle to deal with...how to distribute...)

Of course that does require getting the mold at the $3k figure. For the $8k figure you're looking at selling 200 sets to break even which is significantly more risky, (Possibly too risky)

Don't completely rule out IJ yet. The lower numbers aren't looking that scary.

Haven't ruled it out yet. It's risky but OH so precise! Using the CAD to machine a steel tool, the buttons have a good chance of being perfect on the first try.

But the colors and such? Would a large Injection Molding shop be willing to work with us as we go back and forth about colors? I'll have to see if anyone of them get back to me.

The casters I've spoken with have generally requested "materials specifications"; info on what plastic we want to use. Since the only lead I have is "resin", I've explained the requirements to them in plain english.

Here is my list. Please add, correct, or remove from this as necessary. That way, we can have a more accurate request.

Physically:
come in contact with skin
resist wear and color bleeding
be able to be created with and retain a slight texture
be sturdy enough to withstand years of use
survive reasonably extreme ambient environmental temperatures (perhaps -40 degrees Celcius up to 150 degrees Celcius)
strength for the thin wall of the buttons' shaft

Resin was successfully used in the past (for colored).
Could material used for the original pieces be determined by looking at them?

Color:
create sets in each of five different colored translucent plastics; red, green, blue, yellow, and a dark grey
be lit from behind with with small LEDs
match existing acrylic lenses color in daylight
when lit, match the color of the text on the display
colormatching process will take a few itterations of proofs to determine the correct colors

http://www.intelliwebplus.com/empegbuttons/
Shows the device, the buttons and knob as they appear lit and unlit, and the lenses to match.
The relevant colors on that page are blue, red, and "smoked" (which is the grey).

Incase you're wondering about the current status, here's an update.

I spent last week talking with medium to large injection molding companies. They suggested to make the buttons out of polycarbonate (Lexan) or acrylic. I am asking for quotes using polycarbonate, though, because arcylic is apparently more fragile. Anyone know of problems with using these materials?

For color matching, the possibilities look pretty hopeful. I'll be sending the molders some pieces of the five lense plastics and they'll see what they have access to. Though I didn't know previously, the colors are mixed during the injection process; not before. So, if the tint is wrong, they can just change it. And one molder has offered to produce samples of the final buttons and overnight them to me, leaving his machine idle (profit-less) until I get back to him within 24 hours.

And for the "tool" which will mold the buttons, I'm getting quotes for steel, aluminum, and more temporary materials such as "prehardened P20". Aluminum and steel molds will be out of the budget (confirmed when I see the quote) but the "temoprary tools" may get the job done.

For this coming week, I'll contact a pile of Reaction Injection Molding companies and Resin Transfer Molding companies. Hopefully, that will yeild different prices than the hand casters and injection molding shops. Eventually, a cost-effective solution will be found. Now, back to work I go.

An update from this week's work. I spent the week contacting RIM (reaction injection molding) shops. After reviewing 20 shops, only finding 7 suitable to contact, hearing back from 5; 3 of them confirmed my suspicion that RIM molding was not for this project.

RIM uses urethane as a material. Some say it comes in translucent, some said it didn't. But either way, the polycarbonate offered by injection molders is apparently much more suitable for the project.

A real bummer, because the RIM process seemed less expensive than injection molding. Unfortunately, it seemed to be more widely used for large flat-ish components like car details and ATM machine enclosures.

Next week as the injection molding quotes roll in, I'll be contacting shops that offer Rapid Prototyping and give hand casters another try. Might as well make a tool that's only good for a few thousand sets if that's all that will be made.