[originator]

If anyone has knowledge about commercial design I would appreciate any input.

I designed a PCB that mounts under the glass panel shown in the pic. There is a fingerprint scanner sensor that needs to be mounted on the front of the panel. Shown in the pic is the sensor just lying on top, not in the right position, but it will be in the lower right corner.

I have no idea what is the best material to use for the fingerprint shroud. I can CNC any material, but it can't be metal or conductive. Delrin never finishes well for me on the machine. I can cut acrylic with a laser and get a pretty nice edge on the parts. The shroud has to look very slick, not home brewed. Also, nevermind the glass appearance, the paint has all been scratched up on the rear during experiments, but it will be very slick. The LEDS are too bright on some locations. I need a shroud to look just as elegant, only glass isn't an option.

Shown in the CAD drawing, a .25" rear structure that will mount to the glass/PCB with screws, a .25" bottom piece, a .03" top piece that holds the fingerprint sensor(will be flush, matte finish to hide prints), the green parts are the .125" triangular sides that enclose the under side.

Mounting the sensor flat or parallel with the glass is bad ergonomics. Mounting it perpendicular to the glass is rather awkward as well. The best 'feel' is at around 50 degrees, as the panel mounts on a wall.

The main concerns are: 1) does the design shown look amateur and hacked together, and 2) what material to use to make this so it looks profession and 'expensive'.

Ideally, a matching gloss black on all parts except the top surface that supports the scan sensor. This is all new territory, just trying to sort it out.

Any suggestions welcome. Thanks

[judleroy]

I would cnc a two piece mold and cast the part with hobbycast. The
plastic can be colored so you can take your pick. The quality of the part will be dependent on the smoothness of your mold. Leave the pour spout on the bottom where it will be hidden and leave atleast 1 air release hole on the opposite side of the pour spout.

[High Seas]

originator:

your post had me scraping up old memories from ergonomic/HF engineering days:

You might consider adding a "relieved/rounded" edge all around (well, not the bottom or base).
You'll note most "touch-to-use" items have same -- ie keyboard, mouse etc.
Use the same radius on your product -- give a "well integrated" look and feel. And if you mold the part - good release too.

Cheers - Jim

[originator]

Good points. Thanks guys!

[Bobcurley]

Hello, my first post so be patient. I have used a material with the trade name of acetron gpp with good results. It has alot of similarities to delrin ,but seems to be unaffected by sun light. You can get it in a veriety of colors and I may have some near the shop that is scrap. Most of what I have used is
1.25" or thinner sheet stock. A regular hss steel two flute end mill around 2000 rpm will work good with a feed of approx 10 ipm. Be careful though because the edges of the finished part can be sharp as a razor. Hope that helped some... Bob

[originator]

Thanks for the info on the acetron gpp Bob.

I have a guy making a one piece mold and then making the parts with injection. He uses various material to inject the mold including Delrin, but I will ask him about the acetron just in case.

I believe he is using an EDM machine, and the parts he makes are amazing with any finish you want. I will post the final product in a few days.