Faceplate suggestions. 1

[itsmoked]

I'm working on a controller that would be nice to drop into a recessed hole in a product. I'd like be able to route out a faceplate, using a CNC router, that I can mount the controller to the back of.

I need to be able to run a single 'touch' button on this plate and it will need graphics silk screened onto it.

First thought is acrylic! I have a bunch it and it routes delightfully, can be silk screened, and touch works thru it ~OK.

But I bet UL would not be pleased....

You guys have any suggestions for material that would be ULable?




Keith Cress
kcress -

http://www.flaminsystems.com

 

[btrueblood]

Are you saying the burn rating of the acrylic would be too high? Any idea what rating would be ok - i.e UL94 V-0, V-5, ...? If you need V0, and something sorta like acrylic, maybe polycarbonate? There are also PVC and PVC/ABS blends with good machinability and lots of color choices.

 

[John2025]

FWIW, PVC is self extinguishing.

 

[Skogsgurra]

Could you use a thicker PCB material? Thicker than 1.6 mm, if necessary. FR4 is easily machinable, glass fiber reinforced and can be had with 35 or 70 um Cu on one side or both. The touch button can be part of the front Cu foil and the materiel accepts screen printing.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[mcgyvr]

So which of the thousands of UL standards and specific requirements do you think they will have a problem with?

Define "touch button" are you talking about a resistive/capacitive switch or a tactile dome behind a membrane switch layer...

Is it the 94V-0 aspect that you are concerned about?
ABS?
polycarbonate?

 

[jraef]

Is the "button" a soft button on a touch screen, or are you looking for a discrete button that can have a graphic on it?


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[itsmoked]

Guys thanks for the great responses. I was thinking UL94V-0. I don't know why I failed to included it.

I'm buying boxes a hundred at a time, made out of 94V-0 ABS. So I know that's possible.

btrueblood; Polycarbonate! That would be outstanding. Lots of colors and clear.

I'm going to see if I can hunt up some 94-V0 polycarbonate.

John; I did not realize that. Even easier to machine.

Skogs; I'd forgotten about that option. I did exactly that in fire pump control design as you get the silkscreening for nearly nothing. I'm just not sure the customer will go for PCB green, or Bizarre Yellow, white, Dull Black, Sad Red, or Obvious Blue. I'd be nice to use the board for the circuitry but thru-hole parts will be involved.. Hmmm, need to think about this..

Ah mcgyvr The Stickler. Just the UL94-V0. Touch-capacitive. Not a membrane key-> domy guaranteed-to-fail-in-the-near-future-in-a-most-annoying-way switch.
Tiz good, another who thinks poly might work.

jraef; Definitely not a "smart button". This is a heating appliance that just needs to be touch-on, touch-off.

It now appears I need to include an idiot er, excuse me, an indicator light, that shows the system is on or off. So, that may dictate I need material that light can pass thru, ie ABS may be a problem. I wonder If I could route down to say 10mil thick and light would pass thru the ABS.. That also probably slams using FR4 for the faceplate. :/

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Compositepro]

If you are going to make a part by machining, I would suggest aluminum. It will be stronger and will hold-up to machining forces much better than plastic. Then screen print a polyester (Mylar) film and mount it over the front. You could even just zerox your art onto a mylar transparency. Print on the back side, of course.

 

[ScottyUK]

Is transparent aluminium, to let the light through...?


Polyethylene terephthalate might be worth a look - platic bottles are frequently made of this material. It's mechanically tough but not sure about machinability - probably ok with sharp tools. Good chemical resistance but might be awkward to bond to.

 

[btrueblood]

Clear PVC is a thing. SAN polymer is a clear version of ABS. Both of the prior polymers can be solvent bonded to each other and themselves and to ABS. Don't use polycarbonate if you are thinking of any bonding/silkscreening process, i.e. anything involving solvents.

 

[jraef]

Keith,
I had actually meant to ask whether or not this was a "button" area of a touch screen, or a stand-alone button. Poor wording, sorry.

The reason I was asking is because these are brand new Piezo (very light touch) operated buttons, with or without a lighted ring, and the surface can have standard or custom engravings on them.

http://ab.rockwellautomation.com/push-buttons/specialty/800k-piezoelectric-push-buttons

Unfortunately there is no on-line image of a custom engraved front yet, but if you are interested I can have one of the guys in San Jose get you a sample.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[itsmoked]

Hi Jeff.

I've seen these! Aren't they billed as "vandal 'resistant'"?

Piezo. I had no idea. I thought they were capacitive. Nice.

NEMA 4? Or IP66?

This could work. I do have a hideous depth allowance of only about 3/4" which this switch might exceed..

Thanks.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jraef]

NEMA 4X, also IP69K, so even more stringent than 4X (N4X is 100psi, IP69K is 1160-1450 psi and at 80°C, for food prep wash down requirements). It does stick in 26mm from the front of the box, but that's to the end of the TB, which might be removable. I've seen a sample of it, when it comes back tomorrow I'll take a look and see if it comes off. If not, the button is designed for food prep washdown, so as few nooks and crannies as possible. If that's not important for your application, you could consider building it up on the front of the box, maybe with a spacer or boss, to bring the back side in closer to the door.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[ScottyUK]

That a more commonplace technology than I had realised. APEM make a non-illuminated one which is 10mm deep. Page 9 of

http://www.rapidonline.com/pdf/701480_da_en_01.pdf

Thanks jraef - might have a few uses for those on site where I want a switch which is "operator proof".

 

[jraef]

"Operator proof" switch... Lol
Seems to be a contradiction in terms, but I know what you mean! I had tried the capacitive switches in a few applications where Fred and Barney Flinstone were still employed (does that reference still hold up?). The operators had difficulty discerning the difference between pushing a button and smashing a button "with extreme prejudice". But the capacitive switches were problematic for gloved fingers / fists / broom handles. These piezos seem to be holding up better. Not for lack of effort to kill them of course, it seems to become a game with some operators. I saw a hammer in the drawer at one operator station last month, it has me worried.

Those that you found look nice too. No UL listing on them so we would have a hard time using the here though. Suspiciously however, they look uncannily like the others... As in maybe AB paid to have them UL listed and therefore has exclusive rights to them here? It's been known to happen.




"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[zappedagain]

Do these guys have something you could use?

http://nameplatesforindustry.com/

http://www.ssi-electronics.com/

I've been happy with both their products.

Z

 

[itsmoked]

Hi Zapped.

Thanks for these two links. Nothing they have works in this particular case but I've wondered about both these suppliers.

Keith Cress
kcress -

http://www.flaminsystems.com