Author Topic: How do you make front panel interfaces?  (Read 617 times)

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Offline angdis

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How do you make front panel interfaces?
« on: February 11, 2019, 02:21:22 am »
I keep getting myself into situations where I've made a nice PCB and designed it for an enclosure and everything is smooth sailing until it comes time to make holes in a front panel (typically something that is aluminum and 1.5mm/14ga/60mil thick).

My current solution is the following (and I am not happy with it):
  • Mark up the aluminum front panel with pencil or blueing and a scratch awl, indicating where the centerpoint of the holes are supposed to go.
  • Make a "dimple" on the centerpoints with a spring-loaded punch
  • Drill a small hole using the dimple to guide the drill bit (I am using a hand-held drill)
  • Drill the correct size hole using the small hole as a guide for openings to fit LED lens's, switches, or cable-glands, etc

What happens, even in the best-case-scenarios, is that I make little errors. I have a row of LED's and one is not in alignment. Or worse, the drill snags on the panel and I end up ruining the panel. Whatever the case it's a lot of work and the results are less than satisfying.  :-\ When I look at the front panel, I am just reminded how I screwed it up!


I am looking now into punch and die tools like this (https://www.zoro.com/roper-whitney-hole-punch-kit-13-16-ga-steel-5-kit/i/G5302044/). This particular one is hand-held and has some restrictions about how far from the edge the punch can reach. Also, it's a hand tool and it might be fine for making holes in aluminum studs (which subsequently get covered by drywall) but I don't have a feel for how good the results will be for making holes in front panels that one actually has to look at.

Arbor presses seem like they would be the ideal tool for this kind of activity, but there doesn't seem to be adaptors specifically for punch and die. Arbor presses like the panavise 502 have nice adaptors for IDC connectorization-- but nothing for hole punch (FWIW it's only a 1/4 Ton force).

Finally there's the matter of accurately marking the panel so that you know where to punch/drill or whatever. Are there good solutions for this that don't involve marking stuff and measuring with a caliper?

What techniques do you folks use for making front panels that look good? Is this stuff best shipped out to a manufacturer who can do laser cutting or CNC machining? I am talking here about prototypes (that still need to look sharp) or one-of-a-kind panels.
« Last Edit: February 11, 2019, 02:24:36 am by angdis »
 

Offline rea5245

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Re: How do you make front panel interfaces?
« Reply #1 on: February 11, 2019, 02:41:42 am »
I've experimented with a Proxxon 27100 Micro Compound Table KT 70 underneath a Dremel drill press, with a router bit in the Dremel. I used it to make rectangular cutouts in plastic. It wasn't too bad: I was able to cut straight lines and nice right-angle corners.

I have a project where I'll need to make many enclosures. I'm thinking of having templates laser-cut, then using the templates with a Dremel and router bit to cut out shapes in a plastic case.

- Bob
 
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Offline xdave

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Re: How do you make front panel interfaces?
« Reply #2 on: February 11, 2019, 04:13:23 am »
Often I need to make lots of aligned holes in enclosures when building industrial panels.  Those tend to be quite large steel boxes, 1-2mm gauge, which need to be drilled by hand as they wont fit on a press.

I tape up the front face, mark the centres, then clamp a straight edge across the aligned centres and use a centre punch to mark a dimple for each one.  That way I know they are all aligned along the plane that would be most obvious if one or more were off.  Then use a sharp twist drill bit for holes under 5mm, followed by a step drill bit for holes under 12mm, and for larger holes I use screw-hole punches (photo attached in case you know them by a different name).  You drill a centre hole, typically 10mm using a step drill bit, then insert the punch and tighten with an impact driver to punch a clean hole.

When using a centre punch to mark your drill points make sure you use the correct twist drill to make the hole (and a punch with a matching head).  You need the drill bit to securely stay in the dimple with no wobble and you should get perfectly aligned holes every time.  With alu make sure you use the correct drilling speed and a small dab of cutting oil to stop the tip heating up as it is easy to form a solid lump on the tip which then lets the bit move.  It is very easy to overheat alu when drilling, even if only a few mm thick.

As you mention the drill snagging I'm guessing you are drilling by hand and not on a bench drill (where the piece should be clamped).  It may help to use a step drill in those cases as they are harder to snag when your hand wobbles.  It's not impossible, but harder.  You really should clamp the piece if you can for safety (and never wear gloves when drilling if you plan on retiring with all your fingers).

You could make a drill bit guide for hand twist drilling to clamp to the work piece from any old length of metal or plastic with a hardened steel bushing pressed into it.  It doesn't matter if it rotates as long as it doesn't wobble.  You want it to be about 15-20mm deep to keep the drill bit straight and reduce the risk of it snapping.  If you have to drill the same patterns multiple times you can make up your guide with each of the holes and put locating pins on the bottom to make it quicker.
 
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Offline Kasper

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Re: How do you make front panel interfaces?
« Reply #3 on: February 11, 2019, 04:38:07 am »
Haven't tried this myself, but you can make front panel out of PCB. I'm sure you'd get very precise hole placement. There are threads on this site about it.
 
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Online vaser888

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Re: How do you make front panel interfaces?
« Reply #4 on: February 11, 2019, 06:40:40 am »
For one of my classes we had to make an ac to dc power supply and we had to make the enclosure (to whatever parameters and shape we wanted) out of aluminum sheet metal.
What I did to align and decided where I wanted all the holes was I took a piece of card board or Bristol board, drew and cut out all the hole and test fitted all the components on the card board to see how it looked.
Everything was good with me so all I did was tape my cardboard template onto the area, used a sharpie and outlined all the holes, used an indenter to create a point so the drill bit did not move away and then drilled out the holes. I also used a deburring tool on all the rough edges to makes them not sharp.
I was pretty satisfied with the results.
 
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Offline SMdude

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Re: How do you make front panel interfaces?
« Reply #5 on: February 11, 2019, 07:21:03 am »
Make it from pcb.
That way you can put the correct holes precisely in the correct place.
I make a footprint for my front panels with some indications in assembly layer as to where the board, or any features within the case sit.
I also make face footprints for the parts that will be coming through the panel.
You can choose what colour you want it and you can get it made from aluminum and all printing is applied. Price is extremely reasonable considering what I have paid in the past for front panels.
 
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Offline reboots

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Re: How do you make front panel interfaces?
« Reply #6 on: February 11, 2019, 09:10:28 am »
I started trying to do exactly what you're doing now, with the same tools. Here's how I have improved my process.

For marking the panel, first I model it in Inkscape. Any other vector drawing or 2D CAD program would work too. I print out a 1:1 copy, tape it to the panel, and use a spring-loaded center punch to mark the holes. Easy, accurate, and I can tweak the control layout to my heart's content before committing.

For drilling, you need a drill press and a set of step drills AKA "unibits". Even a cheap drill press will perform better than the hand drill. More expensive step drills will give better results than cheap ones. Even cheap step drills will give better results than the conventional twist drills you may be using now. Accuracy will still require practice and care, but will be more easily obtained. You will still want to start with a pilot hole, preferably the same size as the first step drill step. Use the drill press on its lowest speed. Cutting oil (even WD-40) will help, but you can perform this work dry if you don't want to deal with the mess.

https://en.wikipedia.org/wiki/Drill_bit#Unibit

I spent a fair amount of money on a large, bench-mounted punch, visible at center-left in the picture below, specifically for punching aluminum control panels. I don't recommend this approach. The hole in the workpiece formed to cling to the punch, and the workpiece warped when I tried to remove it. I improvised a stripper attachment, but panel distortion still resulted. Industrial punches are very expensive. The handheld punches will require excessive force in 1.5mm aluminum.

http://reboots.g-cipher.net/mill/mill_positioned.jpg

Don't forget a deburring tool and/or countersink, for that professional touch!

https://www.vargususa.com/Shaviv-Products
 
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Online jmelson

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Re: How do you make front panel interfaces?
« Reply #7 on: February 11, 2019, 11:03:41 am »
Well, the main problem is "jobber's length" drills have a lot of flex, and will drill off-center in thin materials.  There are several ways to deal with it.  One way is to get stub-length or screw-machine length drill bits, which have a very short twist-drill section on a short shank.
These can be ordered from machine tool suppliers.  Another way is to make a thick drill template out of something harder, and clamp your work to the back of the template and drill through.  Not great for one-offs, though.

Or, you can go the "professional" way and get a CNC milling machine.  Small holes can be drilled with short, stiff drills, or even end mills.
All larger holes can be "orbited" out with an end mill, using a G-code program to direct the tool path.  It just depends on how often you face this problem.

Jon
 
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Online james_s

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Re: How do you make front panel interfaces?
« Reply #8 on: February 11, 2019, 11:31:22 am »
I use a step drill, they work much better for drilling sheetmetal than ordinary twist drills. A vertical milling machine is handy too, or lacking access to one of those a cross slide vice on a drill press can do reasonably accurate positioning. In a pinch I sometimes draw a template in Inkscape, tape it to the panel and then eyeball it with a punch.

It's remarkable how good the eye is at noticing small mistakes though, get it off by 2 or 3 thou and it looks crooked. Drives me nuts!
 
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Online Richard Crowley

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Re: How do you make front panel interfaces?
« Reply #9 on: February 11, 2019, 11:57:47 am »
One of my favorite YT videos

 
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Offline angdis

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Re: How do you make front panel interfaces?
« Reply #10 on: February 11, 2019, 01:09:18 pm »
Wow! Thanks!

The more I think about it, the more I like the idea of PCB front panels. I am dealing with exactly the kind of extruded enclosure Mr Mike is dealing with.

Round holes, rectangular openings!!!, silk-screen, everything precise. It is pretty much optimal for one-of-a-kind (or few-of-a-kind) panels!

One can even think about the front panel as a daughter board and put components/connectors on it directly.
 

Offline mac.6

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Re: How do you make front panel interfaces?
« Reply #11 on: February 12, 2019, 03:08:58 am »
A nice trick to make round holes in sheet metal is to fold a cloth multiple times and press it between the plate and the drill.
Should be done on a drill press with the stock really held well. This is really neat to see the cloth being shred to bits but the hole going perfectly round (instead of the classical triangle shape).
Or just stepped drill.
 


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