Saturday, October 4, 2014

Update 10.4.14

My apologies to the viewers of the blog, particularly those that have a vested interest.  Between traveling for work, and finishing up a bathroom project that I’ve put off for 4 years, making / selling a pinball mod I started a while back (cash never hurts in the pinball hobby), I’ve had little time to work on any other pinball projects in between.  The cabinet is nearly finished, all the hardware is on, I’m just waiting for updated vinyl decals.  Even though the playfield will likely be mounted on a rotisserie for a while, I wanted to make sure I got the cabinet done first so I can occasionally drop it in to test for maximum height of playfield objects.
I’ve also been trying to finish stripping my high speed playfield so I can do the overlay and get some practice since this project will also have an overlay for artwork.

Today I didn't get much done, and I really wanted to.  I mean I got some GI installed on the inlane, I finished routing the sling slots and got the solenoids mounted, then I realized I hadn't made all the brackets for the switches on the slings (I made one to test), and looking where it is I realize the bracket is too wide and I'm not sure it's going to be ok with just one if I narrow it down.  I would make some more brackets, but I left my aluminum angle stock at work so it's going to have to wait until Monday.  The other thing I need is a way to mount the roller cherry switch for the ball through to activate the solenoid.  Thankfully I can just model that and print one easily at work.

There’s also a couple of things I felt I had to research in order to get some of the parts done in the near future for this project.  Fortunately a couple projects at work have required me to look into prototyping vacuum forming packaging and prototype molding, exactly what I need to learn about.
The first part I haven’t had much luck with in the past.  I’ve probably contacted 5 vendors in the chicagoland area, and none of them have responded (and this is from my work email with our logo in my signature).  For some reason, if you’re just some engineer looking for some info, thermoforming vendors just don’t care.  Unless you’re in purchasing and can start tossing volume numbers at them, they won’t even listen.  Well I may have found a somewhat local vendor that does both volume and one-off prototype parts:
Vaccuum forming is obviously exactly what you need for making clear ramps (I actually prefer this to steel), but it can also be used for 3d plastics (think whitewater, or congo).  Heck, it can even be used for playfield toys (space shuttle).  My first “dipping my toes into the water” will probably be something I’m not just throwing money away to practice.  I’m going to try recreating one of the 2 broken ramps that nearly every Williams Fire! pinball has.  The mod I just did was some aluminum support brackets (because the hole mounted to the post always breaks), so this adds strength to tie it in, plus the way I did it makes it look like an industrial framework which adds to the aesthetics at the same time.  So basically in order to vacuum form, you need a positive mold.  From what I’ve been reading, the cheapest yet most effective way to do this is honestly just filling it with plaster (the denser the better so it doesn’t break during molding).  Once I have my positive, I’ll ship it to the vendor and have him run off a few dozen parts.  If it works out well, hopefully I can start selling them.  Not sure if I’ll sneak them on ebay as “NOS”, or try contacting Rick from PPS and officially license them.
Ok so 2nd part.  We have a project at work that is low priority, but it’s still a priority.  We don’t want to spend money on tooling because the solution will be resolved on a future product, but that product is still a year away.  I made some prototypes from an RTV mold shot in urethane material, but vendors charge a LOT of money to do this (but 10 parts is still 1/50th the cost a permanent tool).  So obviously this isn’t a part that we can mass produce, even in the hundreds.  Well I’ve been looking into what hobbyists do for molding at home, and it seems like the company SMOOTH-ON is one of the bigger ones, which also have very informative videos.  Now while I’m sure I’ll eventually be able to do a 2-part mold, I’d prefer one that’s one sided (meaning it’s flat on one side).  Well the part I’m working on at work I was able to modify it to do just this, so next week I’m likely going to go to the local BLICK store to pick up some materials to make both the mold and pour the material.  For about $25 you can buy enough rubber material to make a mold to fill a 32oz cup, and the black urethane is the same price.  Urethane doesn’t have quite the durability or strength as a polypropylene or a nylon, but it’s many times better than any 3d printer can produce.  So if I have the ability to start making molds, that means I can make playfield toys, I can make custom mechanisms, and I can even make inserts!  Yea, the same company sells optically clear material (same $25/32oz).

32 ounces of material = 57.75 cubic inches.  I just modeled up a typical 1” insert, and it’s so little material.  So little in fact that I could mold about 400 inserts, or just .06 each

I’ll likely try to use standard inserts wherever possible, but it would certainly be neat to create some custom sizes, or custom patterns that nobody has ever seen before because every manufacturer uses whatever is available in the market.

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