Othermill and SMT pcb

[rom1nux]

Hello,
I'm new on the forum. I search for CNC that can make PCB to quickly create prototypes and i discover the impressive "Othermill". I often use LQFP/TQFP package with pitch of 0.5 mm and track width 0.250 mm.
My english is very rusted so i want to know if i can achieve this precision with the Othermill tools ?
It's possible to create two side PCB with Othermill tools ?
In other words, it's possible to create two side LQFP/TQFP footprint with 0.5mm pitch and track 0.250mm with Othermill tools ? Does someone got picture of this kind of PCB create by Othemill ?
Thanks in advance
(Hope i post in good section and sorry for my bad english)
Rom1nux

[adafruit_support_mike]

The Othermill is accurate to 0.1mm.

You can make SMT PCBs with the Othermill, but it takes a bit of work.

The Othermill has two ways to cut a pattern: milling and engraving. Milling removes all the material around the shapes you've drawn, while engraving cuts the lines you've drawn into the surface.

To mill an SMT PCB the normal way, you'd need a cutting tool smaller than the minimum spacing between your traces or pads. Those can be hard to find, and break easily.

It's easier to make SMT boards by using a pointed cutting tool and engraving the spaces between the traces and pads. You can get narrow, closely-spaced pads and traces that way. Most PCB design programs don't produce that kind of output though, so creating the files that tell the Othermill what to engrave can take a long time.

There's an additional problem that isn't the Othermill's fault, but can make cutting SMT PCBs difficult: it's hard to place a piece of copper clad on the Othermill's work table and keep the top surface of the copper flat to within 0.1mm. You usually have to cut traces about 0.2mm deep to make sure they go all the way through the copper on a PCB more than 5cm across.

That makes lines engraved by a tapered cutter get wider and narrower as they go across the PCB.

[rom1nux]

Hello Mike,

Many thanks for your quick reply and clear explanations, i think i understand the way to go and limitation.
Othermill seem to be a very good product i probably ask Santa Claus to put one under the Christmas tree.

[rtuccio]

I've never used an Othermill, but it does seem like a neat machine that can do some general purpose stuff besides circuit boards, which is nice.

For what you're asking where you need to do fine-pitch work, I'd like to share this link to Prometheus:
MODERATOR EDIT: REMOVED LINK

*Full disclaimer: I'm the designer of Prometheus and we just launched on Kickstarter.
The mentality I had when designing Prometheus was to offer a tool that could provide the detail of a professional machine - those costing over $8,000 - for a fraction of that cost. Our early-bird pricing is $1,899. What sets Prometheus apart is that its custom spindle can run tiny end mills reliably, down to .007 inches (.178 mm) in diameter, which means you could do 7 mil trace and space. On the Kickstarter page, I show exactly what you are describing - a TQFP44 with .250 mm (10 mil) trace and space. The other nice thing is that the board I show there took less than 9 minutes to carve. Also, since Prometheus can use tiny end mills with a square profile, minor height deviations won't affect trace width. You can, of course, still use engraving bits.

-Rocco

This board was carved with Prometheus: 10 mil (.250mm) trace width, 7 mil (.250mm) gaps (7 mil gaps was not required for this design - in later boards I stepped up to 10 mils).

board with atmel chip.png (966.33 KiB) Viewed 1103 times

[rom1nux]

Whaaouu !
Amazing, this is exactly what i look for.
I'm going to look at your kickstarter project this evening.
Thank for information.

[rtuccio]

Thanks Rom1nux, glad you like it.

-Rocco

[adafruit_support_mike]

@rtuccio: Your post is legitimately on-topic, but we don't allow Kickstarter links in the forum. We're already a big enough target for link-spam as it is.