Cheap CNC Machine to Cut Front Panels? - Page 1
Forum section: electronics / projects

author: RCHRDM
author_rank: Regular Contributor
timestamp: September 11, 2018, 05:45:28 pm
content: Cutting square or rectangular holes in plastic project boxes for LCDs and other items is not easy to do neatly.Has anyone tried using a cheap milling machine such as this one for cutting these openings?https://www.amazon.com/dp/B07169D9JQ/?coliid=I3D6B58EHVQUJE&colid=1J8Z8WV7SG33J&psc=0&ref_=lv_ov_lig_dp_itRichard

author: jmelson
author_rank: Super Contributor
timestamp: September 11, 2018, 07:54:26 pm
content: Quote from: RCHRDM on September 11, 2018, 05:45:28 pmWell, the first thing to know is that you cannot get sharp internal corners with milling! You will get an internal radius that is no smaller than the radius of the cutting tool. The machine doesn't look TOO BAD, but the spindle looks quite flimsy, and may deflect a lot, even in plastic.Jon

author: rstofer
author_rank: Super Contributor
timestamp: September 11, 2018, 08:54:25 pm
content: You can always rough cut the rectangular openings and then do the final trim with a smaller diameter bit.The motor is fairly high RPM and this is a good thing when cutting plastic.I don't imagine it will hold very tight tolerances but it will probably be good enough for panels.

author: Benta
author_rank: Super Contributor
timestamp: September 11, 2018, 09:27:01 pm
content: Great for Balsa wood, and that's it.Concerning motor speed: no, high speed isnotgood for plastic, it makes it melt. What you need is a sharp milling tool at moderate speed with a relatively thick chip. This mandates a machine that's sturdier than this one.

author: t1d
author_rank: Super Contributor
timestamp: September 12, 2018, 12:17:07 am
content: One trick for electronic panels is to create the panel as a PCB and have a cheap board house make it for you. There are many advantages, as you can imagine. Generally, you create a board with no copper. But, sometimes, for designs needing RF isolation, etc., you might use a copper plane/pour and connect it to the shield. Drilled holes are precise, in location and diameter. Labeling is done, via the silkscreen. Bitmap graphics can be added. YouTube has some videos...Video #1. And others?https://www.youtube.com/results?search_query=pcb+front+panel

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 12, 2018, 12:20:24 am
content: I came across the trick of using aluminium circuit boards as front panels. That's more structural and tends to look better. Most board houses can do this at a reasonably moderate cost.

author: ggchab
author_rank: Frequent Contributor
timestamp: September 12, 2018, 01:20:57 pm
content: I am using a small CNC machine I built myself to make front panels with aluminum and plastic sheets. Of course, this is for hobbyist projects, this is not perfect and needs lot of time and patience ...

author: Pinkus
author_rank: Frequent Contributor
timestamp: September 12, 2018, 01:23:59 pm
content: Quote from: Mr. Scram on September 12, 2018, 12:20:24 amVery interesting. I have done this with regular PCBs but not with aluminium PCBs. Can you show a photo?

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 12, 2018, 02:05:54 pm
content: Quote from: Pinkus on September 12, 2018, 01:23:59 pmWill a thread do?https://www.eevblog.com/forum/reviews/aluminium-front-panels-made-by-the-pcb-fab/

author: Pinkus
author_rank: Frequent Contributor
timestamp: September 12, 2018, 03:20:54 pm
content: Thanks!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 12, 2018, 03:38:15 pm
content: For hand cutting, a fretsaw like this works wellhttps://www.zoro.co.uk/shop/hand-tools/saws---coping--fret-and-flexisaws/70-fs1r-(fs70)-fret-saw-frame/p/ZT1008912X?utm_campaign=pla-Hand+Tools+-+&utm_source=google&utm_medium=shopping-pla&utm_keyword=ZT1008912X&istCompanyId=6aa6787b-063e-4414-802d-129f235df603&istItemId=wtqirimrql&istBid=tztx&gclid=CjwKCAjw8uLcBRACEiwAaL6MSV9lVM_DLaM5FpAolUtZq-OsbX4HYDheciYjol_LahWtMPApc8EtvRoCYrgQAvD_BwEThen finish with a file.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2018, 09:25:58 pm
content: I built a front panel from two sheets of Acrylic with a paper printout from the CAD tool sandwiched in between. The actual drilling was done on a small converted CNC mill (Grizzly GO704).Sure glad I bought my mill before Trump tacked on a $345 tariff.http://www.grizzly.com/products/Mill-Drill-with-Stand/G0704I plan to use the sandwich scheme in the future. It works well, looks nice and the lettering is protected by the top sheet of Acrylic.The good news is that I don't have any square openings. If I did, I would do as I suggested above and rough cut the opening with a large diameter cutter (to lessen the chance of breaking) and then clean it up with a small diameter cutter. If absolutely necessary, I could square up the remaining radius with a file but I would really like to avoid that.

author: Apollyon25_
author_rank: Regular Contributor
timestamp: November 15, 2018, 02:47:34 am
content: You can get a 90deg corner by overmilling in one direction slightly...

author: Wan Huang Luo
author_rank: Regular Contributor
timestamp: November 15, 2018, 12:17:38 pm
content: Just get a broach tool and be done with it

author: rstofer
author_rank: Super Contributor
timestamp: November 15, 2018, 03:35:21 pm
content: Quote from: Apollyon25_ on November 15, 2018, 02:47:34 amThis will work perfect if the gadget being mounted has a flange. Not all meters do but a lot of the better ones do.To work, this technique would be better done with a small diameter bit. As I indicated above, it is possible to rough cut the outline (say 0.010" small on each side) then go back with an 1/8" bit (or smaller) and clean up the edges and overcut the corners, if desired.

author: Wolfgang
author_rank: Super Contributor
timestamp: November 15, 2018, 03:52:17 pm
content: ... your machine looks a bit too cheap to give decent results.I have a Hi-Z400T from CNC STEP in Germany, and this one cuts and mills all my Hammond Aluminium boxes.Machine here:https://www.cnc-step.com/cnc-router-400x300-s-400t-ballscrew/

author: cdev
author_rank: Super Contributor
timestamp: November 15, 2018, 08:53:55 pm
content: For acrylics, simply having a decent X-Y table is likely to make a big difference for cutting holes neatly.That (analog computer!?!) looks really nice.Really nice, I would be just terrified to screw that up. It came out great.

author: cdev
author_rank: Super Contributor
timestamp: November 15, 2018, 09:15:42 pm
content: With care and going slowly one can cut the rectangular opening in acrylic precisely with an X-Y table and a drill press going sideways but one is going to need to use a fine hand file to get the square corners. A diamond file with a square corner will do it handily.Quote from: rstofer on September 11, 2018, 08:54:25 pmFor doing this I want to be able to temporarily affix (glue?) my laser printed out template to my piece of plastic.glue it well enough to not tear when the holes are being drilled and filed, and then come off completely in soap and water without my having to scratch it.Kind of like with toner transfer PCBs except with the omission of the scratching of the PCB and heat and toner and the substitution of elmers glue. (Its all Ive got, and it seems to be water soluble enough to not require my scratching it to get it off, given enough time)Elmers glue to glue it on, and later soaking and maybe toothbrush to get it off?