PCB on the Shapeoko

Hi all looking for a little help on some speeds and feeds. Does anyone have experience with Copper clad FR4 on the Shapeoko? I need to cut my first PCB and it’s 1/8" single side copper clad FR4 Here is a Link.

I was planning on using a .03 ball engraver from Lakeshore, with a DOC of .01" for the traces.

For the holes, and to release the part form the stock, I was going to use a 1/16" 2 flute from Kodiak with a DOC of 1/8".

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FR-4 makes some nasty dust. I’d recommend FR-1, especially for single sided boards.
I’ve used this end mill with success, but I usually use cheap, generic “PCB engraving bits”.
Been a while, but I recall it being really easy to cut… Go fast, make sure it is FLAT.

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How do you do thru-holes on cnc produced boards?

I’ve been wanting to test surface mapping /autoleveling for a while, I hear it’s almost a requirement to get perfect PCBs. bCNC and EstlCam have this features, probably others.

I did pull off a PCB or two without autoleveling, they turned out “ok-ish”. But it was two years ago and I can’t find my old files/settings right now.

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Ohhh ya. I have all the stuff for cutting, sanding, and working with carbon fiber…so I will be suited up like a spaceman.

You do a regular hole… lol just kidding. If you need a via, to connect copper from one side to the other then make a hole put a small piece of wire in it, and solder on both sides. In my case everything is through hole and only requires a single-sided PCB, so I got lucky😁

This is my exact reason for going with 1/8" thick FR4. If I’m cutting.01" deep and +.005" somewhere I don’t have to worry about cracking the board or cutting through to the other side. Admittedly just buying extra thick stock is probably not the right way to approach it. But for the extra dollar fifty it was worth it.
How does that old saying go, measure once, cut twice, throw it away because you only measured once? Same thing will work for the thickness right? :roll_eyes:

FR4 is fiberglass - wear a HEPA respirator! (you’re SOL unless you have one) or just buy them?

That’s what I started doing…pretty cheap if you don’t need it today.

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Ya, I have my fair share of microwave popcorn stacked up. Unfortunately this project is not for me, I’m doing this for a friend who is skeptical of PCBs. My OCD can’t take watching him wire one more circuit dead-bug style. So I offered to make a couple for him.

To be fair though Its 5"X 6" with very few traces, and requires cut-outs around the edge, and will require slots for component hold downs. It would be a fairly expensive single-sided PCB for a lot size less than 10.

@gmack personally I prefer Advanced circuits and they ship stuff with cool free extras😁.

EDT… I can’t type :grimacing:

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I recently made a fairly simple PCB with FR-1 with decent result with a stock XXl and Makita. I mostly followed this guide: https://hackaday.com/2018/01/04/guide-why-etch-when-you-can-mill/ and https://support.bantamtools.com/hc/en-us/articles/115001671734-FR-1-PCB-Blanks.

I first flattened a waste piece of MDF and taped the board to that. I couldn’t quite wrap my head around getting the auto-leveler mentioned in the article working with the Shapeoko but it turned out okay. I then used one of the cheap 10-degree engraving endmills that’s listed in the HaD article and ran it at 300mm/min at a depth of 0.2mm. I’d recommend a set of PCB drills if you need to make any small holes. Watching it drill a bunch of tiny holes was honestly my favourite part. Cutting out I just followed the ones recommended on the Bantam Tools website:

1/8" flat end mill
Feed rate: 14.173 in/min (360 mm/min)
Plunge rate: 1.81 in/min (30 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.005" (0.13 mm)

(Ignore the clumsy soldering job)

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Ok ladies and gents. Here’s a picture of the finished PCB,first attempt, but it went well. I’ll post speeds and feeds later. Only one end mill was harmed in the making. As it turns out you shouldn’t rapid at 100 ipm into FR4.

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I’m a little surprised that you can get that kind of result by using the tape hold down method.

PS. I’m usually reluctant to download photos separately to view them. Most photos here just show up in the post.

Why’s that?
I’ve used double sided Scotch tape on PCBs.

Damnit… I uploaded it on my phone, now to edit the post. The tape trick worked well, I was ±.003 in.

The cuts looked mighty consistent, and Mr.C confirms “.003”. I’m going to have to try this out.

@TheSilentEngineer are you using C3D’s PCB software?

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No actually. The person that wanted the layout did the model in Fusion 360, so I just ran with that. I’ve heard good things about C3D’s stuff though. I can’t post the Fusion file as it’s a prototype for a product that my friend is developing but I’ll grab the speeds and feeds.

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I’m well versed in DipTrace software, but I’ve always sent Gerber files off to a PCB shop for manufacturing.

There’s another thread on here about doing this. I remember reading it.

I’ve never heard of Dip Trace I’m guessing it’s pretty similar to most PCB layout software. I grew up using Eagle which is now part of Fusion 360. And I’ll admit you’re right to heck of a lot easier having a dedicated Fab house make a board for you. :roll_eyes: The challenge was fun though, and knowing that I can do it if I want a quick one off is really cool. I’m not sure how well this would turn out if I had to do a two-sided board. But I’m sure that’ll be a future project.

It is easier, but not more efficient for one or two boards. If I can do as well as you on milling a board, I’ll be happy! :grin:

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So as promised here are the details of the build. I’m working with a layout and the materials provided by a friend. He needed a one off board so I figured, hey, why not! The design was done by him in Fusion 360, and I did the CAM.

Material:
1/8" single side copper clad FR4 form Mcmaster link here

Tools:
.03" ball engraver from lakeshore. you can find them here.
Slotting, holes, and part release were done with a 1/16" 2 flute from Kodiak.

Workholding:
Simple blue painters tape and superglue. That’s on a leveled waste board, shout out to @RichCournoyer for some good info on how to do it right! you can find it on this Post. But overall it’s ±.003" over the entire stock.

Speeds and feeds:
Did some digging around and I found a wide range of speeds and feeds. GWizard recommends high RPM and slow speed think 25000K and 12 IPM for the Kodiak. This seemed to run counter to everything I’ve heard about FR4. So I decided to stray from the course and go with high speed and highish feeds. The risk of course is rubbing and ware on the endmill, but since there’s so few cuts It’s a risk I’m willing to take. There were three Ops, a Trace for the…traces, a 2D pocket for the holes and slots, and a 2D Contour for releasing the part.
Trace:

2D Pocket:

2D Contour:

So with that out of the way here’s the results. Good clean finishes all the way around, and no damage to the copper. The only problem was buildup of the material in the cuts, although it wasn’t due to the flutes not clearing the material. The adhesive on the tape built up in the cut and created a slurry of fiberglass and tape. So I’d recommend a different pathing strategy or perhaps a different form of workholding. Another worthwhile note is the use of multiple passes on the engraving. I’ve found that it prevents rapid loading of the tool due to height variations in the board. So that’s it!

PS. If anyone knows how to fix the formatting on the pictures please let me know…

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oO
are those giant capacitors ?
what kind of amperage requires PCB traces as large as a finger ?