Custom Silicon Switches? Anyone Use? Know any mfgs in Los Angeles CA? - Page 1
Forum section: electronics / projects

author: jnz
author_rank: Frequent Contributor
timestamp: August 26, 2015, 09:18:46 pm
content: So...I'm thinking about putting this type of switch in my next project. Custom molded, graphite pads on the switch that connect small signal copper or tin tracks on the PCB. What I don't know is...Is there a downside to using a switch like this? I like that they are their own spring, they shouldn't really wear out if made properly I would think... Maybe they are harder to debounce? I don't really know the pros and cons. I just know I can afford these for the project and could not afford custom injection moldingI'll have about 10-20 different labels for each switchDoes anyone have a good company with a USA office I might be able to look into?And I'll be in LA for a few days, so if anyone knew someone I could go visit, that would be even better!Any thoughts?

author: jnz
author_rank: Frequent Contributor
timestamp: August 27, 2015, 04:57:18 pm
content: No one uses silicon switches? What do you use in you want backlighting in a product? Injection molded ABS?

author: edavid
author_rank: Super Contributor
timestamp: August 27, 2015, 05:34:27 pm
content: I think your subject line is confusing people... you mean silicone, not silicon.

author: LabSpokane
author_rank: Super Contributor
timestamp: August 27, 2015, 05:50:41 pm
content: You're thinking silicone.What is your volume? Is this a hobby project or commercial?Most of these are made using compression molding with carbon pucks inserted into the mold prior to adding the silicone. The switch matrix is then cooked under pressure until it vulcanizes. These molds are not as expensive as injection molds, but still are spendy. The membrane that gives the switch its "snap" is very thin - thus challenging to machine both halves of the tool to fit very closely.You will also need to silkscreen the PCB contacts with carbon.These types of keypads are generally sold as an integrated solution by various custom manufacturers. i.e. PCB + Key matrix + electronics as necc.

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 27, 2015, 06:17:49 pm
content: Are you looking for full-custom?Are you familiar with the kinds of purchase volumes and tooling costs associated with that?Do you have that kind of volume and budget to support that?It is extremely doubtful that any of those are made in the US. They probably all come from Asian manufacturers.There are generic arrays of white silicone buttons available from vendors like Sparkfun and Adafruit and Livid Instruments (and likely others).https://www.sparkfun.com/products/7835https://www.adafruit.com/products/1611http://shop.lividinstruments.com/individual-diy-buttons/Marking them is a fundamental problem. Because the buttons are so soft, you can't keep anything on the top surface for very long before it starts wearing off from users pressing the buttons.

author: jnz
author_rank: Frequent Contributor
timestamp: August 27, 2015, 11:22:48 pm
content: Silicon Silicone Tomato Tomahtowe ...Yes, silicone.Um, yea something like 12,000 a year ish.It's the mfg part on one hand, but also interested in the PCB side with the trace/pad and factors like that.

author: jnz
author_rank: Frequent Contributor
timestamp: August 27, 2015, 11:25:11 pm
content: Quote from: Richard Crowley on August 27, 2015, 06:17:49 pmUnfortunately I figured that might be the case. At least North American design company with overseas production then.QuoteYea, that's the other issue. I do want to put pictograms on these, or more likely inverse is so that only a little light is visable through. Maybe silicone isn't what I want, but I'm fairly certain I don't want many part injection molded ABS as the design alone would be ridiculously complex.I suppose I could consider fairly large mechanical switches with really great tacticle feel with a silicon or other material over them, but I'm not sure if that would be 'better'.

author: LabSpokane
author_rank: Super Contributor
timestamp: August 27, 2015, 11:28:05 pm
content: Quote from: jnz on August 27, 2015, 11:22:48 pmThis isn't in LA, but Esterline/Advanced Input Systems sells every keyswitch technology aside from maybe Cherry switches. You'll need to fly to Spokane to visit, but it would be worth your time.

author: jnz
author_rank: Frequent Contributor
timestamp: August 28, 2015, 02:48:07 pm
content: Quote from: LabSpokane on August 27, 2015, 11:28:05 pmAh Spokane (SpoCompton), little city size, big city problems!I'll try both of them! Thanks for the ideas!

author: LabSpokane
author_rank: Super Contributor
timestamp: August 28, 2015, 03:22:40 pm
content: Quote from: jnz on August 28, 2015, 02:48:07 pmThings have gotten a lot better here. Coeur d'Alene is a major destination now - a far cry from the logging town it used to be.Advanced Input is *definitely* going to be on the higher price side - so you've been warned.But, they do have a lot of options to choose from and do have about 25 years of experience with elastomers. If you're going to have an elastomer keypad that is behind a plastic bezel, I'd strongly recommend using a 3rd party to integrate both. The real problems with elastomer keypads aren't debouncing - it's the force curve and sticking in the bezel holes.As for your desire to have a backlit keypad, that is no problem. They will make a clear key matrix then coat it black with a reverse silkscreen on top with "cutouts" for the legends to let light through. That's a pretty standard technique now.I just read your original post, and if you can't afford tooling right now, consider a membrane type keypad as well. If you want a tactile feel, AIS has snap-dome type switches that they place under the formed buttons. No matter what you do, there is going to be *some* tooling cost. For the membrane switches, you'll need a few steel rule dies and an embossing tool, and silkscreens.If you just want a plain rubber keypad over a PCB, then it might be a coin toss on costs. But a fully exposed rubber keypad will have some durability issues.