Tips for working with Enclosures?

txmarsh · 2010-08-30 09:36

I've recently started to enclose my project in standard plastic enclosures. The simple act of creating a number of holes in a box that are well aligned and spaced has proven to be more difficult then I initially thought. Normally I start by designing and printing a template. I then apply that template to the box and center tap each hole to be drilled. After center tapping I use a small "hobby" drill (hand held manual drill) to make a guide hole. Last I drill the full sized hole with an electric drill. This has provided acceptable results but I was wondering how others approach enclosures. Also, what techniques do you use to apply lettering?

Thanks!
Tim

Ron Czapala · 2010-08-30 09:57

txmarsh,
Making a presentable enclosure is often the hardest part of project. Cutting rectangles, squares (and other non-round openings) can be a real pain.
I have a drill press which helps with precision drilling plus you can feed the bit very slowly so it doesn't grab.

I recently bought a digital caliper from Harbor Freight for more precise measurements.

You can buy nice LCD mounting kits with a clear center and black edging for attractive LCD mounting.

Radio Shack has some LED holders that improve the appearance of standard size LEDs.

Digikey carries a nice assortment of project boxes - I like the ones by Hammond Mfg.

tdlivings · 2010-08-30 10:28

Method I use is to tape a piece of fine grid graph paper to the box and then mark part locations on it. Carefully setting the parts on the graph paper to design the layout also covers how much distance is needed between parts. I will admit with many years of making custom instrumentation to having two rotary switches occuping the same space on the back of the panel with my elegant layout when I was not watching how close I could put them.
I like your templete idea and I have used that method also. Frontpanel Express where you can order a drilled and lettered panel from supplies free software to layout the panel and I have used that to make the templete I taped to a panel or box. I think they still exist.
For lettering Avery label maker with white on clear or black on clear. Does not look store bought but works.
I have seen some real good almost store bought looking done by using your PC and a cad or paint program to make label you glue on the box.

Tom

tdlivings · 2010-08-30 11:00

FrontPanel Express does still exist.
http://www.frontpanelexpress.com/

T Chap · 2010-08-30 11:14

Short of having a CNC type machine for drilling precise holes, the next best thing would be to use calipers to score the X and Y for the pilot drilling. Use the sharp edges on the calipers to mark the X, then re-adjust and mark the Y hash marks. This is far better than trying to measure and mark with a pencil or similar method. Then, if you can put the part in a clamp and use a drill press, you will get decent results with practice.

Rest one point of the caliper on an edge of the enclosure, lock the caliper in place with the thumbscrew, the score the surface. These things have very sharp points and will scratch almost anything.

HollyMinkowski · 2010-08-31 00:17

I like to print my front panels and
then place a thin sheet of clear
plastic in front of it. You get a really
professional result. You can drill the
holes using the printed front panel
as a guide. A small drill press is a must
to get things exactly right.

Buy standard plastic boxes that have
a front panel that fits into a slot. You
can then use one thin clear panel as a
back panel and drop your printed panel
in front of it and then slide in the clear
front panel.

LoopyByteloose · 2010-08-31 03:53

Thermoplastic presents a lot of problems as it often melts while being worked.

Cooling with a water drip system is useful, though a bit messy.

And finding other drill bits than the standard twist drill may help. I use a wood working twist drill that has a point in the middle for centering, but cuts the outside edge first. And there are some specialized plastic drill bits that are useful.

Slow speed and low pressure are always necessary with thermoplastics. You never want to melt.

Ultimately, I usually end up doing a lot of hand work. If I need a flat straight finished edge or surface, a mill bastard file is a useful tool. Trimming and smoothing the edges of large sheets can be easily done with a carpenter's block plane. Cut is often done with a hacksaw and the blade is set up to cut on the pull rather than the push for better control. A hand drill saves me the trouble of dragging power cords and frustrations of too much speed.

Leon · 2010-08-31 05:08

I normally use a pillar drill with a tapered reamer for large holes, and a paper template created with my PCB package to drill the pilot holes. Smaller holes are drilled directly. I once used my little Taig lathe with the milling attachment when I needed some really precise holes in a small die-cast box. A full-size milling machine would a nice thing to have for larger boxes. A separate panel overlay can disguise a lot of mistakes, provided the holes that need to be in-line are.

Phil Pilgrim (PhiPi) · 2010-08-31 08:48

Molded and die-case boxes with lids can be difficult to work with, due to the slight taper built into their sides to facilitate extraction from the molds. I much prefer extruded enclosures with self-contained slots for the PCBs and flat, screw-on end panels. Drilling/milling holes in something flat is much easier than wrestling with an entire enclosure. Plus, if you make a mistake, you haven't ruined the whole thing -- just a small piece of metal or plastic that can be replaced easily and cheaply.

-Phil

lardom · 2010-08-31 19:00

For square and rectangular holes I found a wood chisel works best. I may trace the shape onto paper and place masking tape to hold it in position. You can still see the pencil marks. Once I have a clean score I will make 45 degree cuts into the corners then snap the edges off. For me it works better than a Dremel or filing. I also like a digital vernier caliper.

txmarsh · 2010-09-01 17:42

These are all great tips... thanks! Boy I sure wish I had a CNC though... making an enclosure is more like art than science... and I'm not artistic. ; )

PJAllen · 2010-09-01 17:55

Get a drop shear, a band saw, and a finger brake. That stuff is expensive, but I've worked places where they had them (2, 3); layout and cut and bend some stock laying around, pretty cool.

Improvise, and workout those inevitable [measure twice, cut once...]eccentricities, with a small round file, a cross-cut file, and a nibbler, invaluable.

Post Edit -- Masking tape, too. Plot and mark your stuff out on it. It protects your surface during your work. Any adhesive residue comes off with isopropyl.

lardom · 2010-09-01 18:49

txmarsh, a cnc would be major. I expect to make copies of my machine for other people. Designing and making the original was fun but making multiple copies by hand is boring. Automation is a dream I think a lot of us have.

yarisboy · 2010-09-11 05:05

I started by having the extruded enclosure on hand while doing the layout. If you have the box first you can move components and connectors around to make a better fit. I bought an X-Y drill vise for my drill press at Harbor Freight for $50. To cut nice clean holes in the aluminum end plates you need a small carbide mill bit and center drills. Using a 0-12" digital dial caliper for relative locations allows good results with the poor man's Bridgeport.

Tips for working with Enclosures?

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