DIY Vacuum Table Enhances PCB Milling

CNC milling a copper-clad board is an effective way to create a PCB by cutting away copper to form traces instead of etching it away chemically, and [loska] has improved that process further with his DIY PCB vacuum table. The small unit will accommodate a 100 x 80 mm board size, which was not chosen by accident. That’s the maximum board size that the free version of Eagle CAD will process.

When it comes to milling PCBs, double-sided tape or toe clamps are easy solutions to holding down a board, but [loska]’s unit has purpose behind its added features. The rigid aluminum base and vacuum help ensure the board is pulled completely flat and held secure without any need for external fasteners or adhesives. It’s even liquid-proof, should cutting fluid be used during the process. Also, the four raised pegs provide a way to reliably make double-sided PCBs. By using a blank with holes to match the pegs, the board’s position can be precisely controlled, ensuring that the back side of the board is cut to match the front. Holes if required are drilled in a separate process by using a thin wasteboard.

Milling copper-clad boards is becoming more accessible every year; if you’re intrigued by the idea our own [Adil Malik] provided an excellent walkthrough of the workflow and requirements for milling instead of etching.

Homebuilt CNC Software, Brewed To Taste

Mainstream productivity software from the big companies is usually pretty tight, these days. Large open source projects are also to a similar standard when it comes to look and feel, as well as functionality. It’s when you dive into more niche applications that you start finding ugly, buggy software, and CNC machining can be one of those niches. MillDroid is a CNC software platform designed by someone who had simply had enough, and decided to strike out on their own.

The build began with the developer sourcing some KFLOP motion control boards from Dynomotion. These boards aren’t cheap, but pack 16MB of RAM, a 100-gate FPGA, and a microcontroller with DSP hardware that allows the boards to control a variety of types of motor in real time. These boards have the capability to read GCODE and take the load off of the computer delivering the instructions. With the developer wanting to build something robust that moved beyond the ’90s style of parallel port control, these boards were the key to the whole show, also bringing the benefit of being USB compatible and readily usable with modern programming languages.

To keep things manageable and to speed development, the program was split into modules and coded using the author’s existing “Skeleton Framework” for windowed applications. These modules include a digital readout, a jogging control panel, as well as a tool for editing G-code inside the application.

For the beginner, it’s likely quite dense, and for the professional machinist, industry standard tools may well surpass what’s being done here. But for the home CNC builder who is sick of mucking around with buggy, unmaintained software from here and there, it’s a project that shows it doesn’t have to be that bad. We look forward to seeing what comes next!

Want to see what else is out there? We’ve done a run down of DIY-appropriate CNC software, too.

Bandpass Filters from the CNC Mill

A bandpass allows a certain electrical signal to pass while filtering out undesirable frequencies. In a speaker bandpass, the mid-range speaker doesn’t receive tones meant for the tweeter or woofer. Most of the time, this filtering is done with capacitors to remove low frequencies and inductors to remove high frequencies. In radio, the same concept applies except the frequencies are usually much higher. [The Thought Emporium] is concerned with signals above 300MHz and in this range, a unique type of filter becomes an option. The microstrip filter ignores the typical installation of passive components and uses the copper planes of an unetched circuit board as the elements.

A nice analogy is drawn in the video, which can also be seen after the break, where the copper shapes are compared to the music tuning forks they resemble. The elegance of these filters is their simplicity, repeatability, and reproducability. In the video, they are formed on a CNC mill but any reliable PCB manufacturing process should yield beautiful results. At the size these are made, it would be possible to fit these filters on a business card or a conference badge.

Continue reading “Bandpass Filters from the CNC Mill”

Soundproofing A CNC Mill Conversion

The Proxxon MF70 is a nice desktop sized milling machine with a lot of useful add-on accessories available for it, making it very desirable for a hacker to have one in his or her home workshop. But its 20000 rpm spindle can cause quite the racket and invite red-faced neighbors. Also, how do you use a milling machine in your home-workshop without covering the whole area in metal chips and sawdust? To solve these issues, [Tim Lebacq] is working on Soundproofing his CNC mill conversion.

To meet his soundproof goal, he obviously had to first convert the manual MF70 to a CNC version. This is fairly straightforward and has been done on this, and similar machines, in many different ways over the years. [Tim] stuck with using the tried-and-tested controller solution consisting of a Raspberry Pi, an Arduino Uno and a grbl shield sandwich, with stepper motor drivers for the three NEMA17 motors. The electronics are housed inside the reclaimed metal box of an old power supply. Since the Proxxon MF70 is already designed to accept a CNC conversion package, mounting the motors and limit switches is pretty straightforward making it easy for [Tim] to make the upgrade.

Soundproofing the box is where he faced unknown territory. The box itself is made from wooden frames lined with particle board. A pair of drawer slides with bolt-action locks is used for the front door which opens vertically up. He’s also thrown in some RGB strips controlled via the Raspberry-Pi for ambient lighting and status indications. But making it soundproof had him experimenting with various materials and techniques. Eventually, he settled on a lining of foam sheets topped up with a layer of — “bubble wrap” ! It seems the uneven surface of the bubble wrap is quite effective in reducing sound – at least to his ears. Time, and neighbours, will tell.

Maybe high density “acoustic foam” sheets would be more effective (the ones similar to “egg crate” style foam sheets, only more dense)? Cleaning the inside of the box could be a big challenge when using such acoustic foam, though. What would be your choice of material for building such a sound proof box? Let us know in the comments below. Going back many years, we’ve posted about this “Portable CNC Mill” and a “Mill to CNC Conversion” for the Proxxon MF70. Seems like a popular machine among hackers.

CNC Robot Makes a Move

Another day, another Kickstarter. While we aren’t often keen on touting products, we are keen on seeing robotics and unusual mechanisms put to use. The Goliath CNC has long since surpassed its $90,000 goal in an effort to put routing robots in workshops everywhere.

Due to their cost and complexity, you often only find omni-wheels on robots scurrying around universities or the benches of robotics hobbyists, but the Goliath makes use of nine wheels configured as three sets in a triangular pattern. This is important as any CNC needs to make compound paths, and for wheeled robots an omni-wheel base is often the best bet for compound 2D translation.

coordinate drawingWhat really caught our eye is the Goliath’s unique positioning system. While most CNC machines have the luxury of end-stops or servomotors capable of precise positional control, the Goliath has two “base sensors” that are tethered to the top of the machine and mounted to the edge of the workpiece. Each sensor connects to the host computer via USB and uses vaguely termed “Radio Frequency technology” that provides a 100Hz update for the machine’s coordinate system. This setup is sure to beat out dead-reckoning for positional awareness, but details are scant on how it precisely operates. We’d love to know more if you’ve used a similar setup for local positioning as this is still a daunting task for indoor robots.

A re-skinned DeWalt 611 router makes for the core of the robot, which is a common option for many a desktop milling machine and other bizarre, mobile CNCs like the Shaper Origin. While we’re certain that traditional computer controlled routers and proper machining centers are here to stay, we certainly wouldn’t mind if the future of digital manufacturing had a few more compact options like these.

Milling a Flow Sensor to Safeguard a Laser Tube

Powerful lasers get powerfully hot and if you don’t keep them cool you’ll pay the price. After two such experiences [NixieGuy] got smart and milled this flow sensor as a failsafe.

Laser cutters are awesome. But acquiring one can be expensive, and keeping them in working order is no small feat. From the gunk that builds up as a byproduct of vaporizing the cutting stock, to keeping the optics focused correctly, it’s a game that forces you to become a laser cutter operator and not merely a user. One of the worst things to deal with is having to replace a burnt out laser tube. They do have a life to them but in this case the filter on the water cooling system clogged and the tube cooked itself. Twice.

Flow sensor shown in the upper right.

This flow sensor now acts as an interconnect with the laser enable line. Starting with an acrylic rod, [NixieGuy] machined out a center hole for a magnetic stopper, then milled three channels for water to pass around it. Each end of the rod was turned on a lathe to interface with plastic tubing of the water cooling system, and a slot was milled on the outside for a reed switch.

The demo video is below. You can see that when water flows it pushes the magnetic stop up (against gravity) where it engages the reed switch, allowing the laser to operate. If something impedes the flow of water (even if the pump still runs) the laser will be disabled and (hopefully) prevent future tube loss.

Want to see some of the oops moments faced by many a laser cutter operator? Check our guide on how to fail at laser cutting.

Continue reading “Milling a Flow Sensor to Safeguard a Laser Tube”

Your Work Won’t Move with a Magnetic Drill Press Vise

Setting up your workpiece is often the hardest part of any machining operation. The goal is to secure the workpiece so it can’t move during machining in such a way that nothing gets in the way of the tooling. Magnetic chucks are a great choice for securely and flexibly holding down workpieces, as this simple shop-built electromagnetic vise shows.

It looks like [Make It Extreme] learned a thing or two about converting microwave oven transformers to electromagnets when they built a material handling crane for the shop. Their magnetic vise, designed for a drill press but probably a great choice for securing work to a milling machine, grinder, or even a CNC router, has a simple but sturdy steel frame. Two separate platforms slide on the bed of the vise, each containing two decapitated MOTs. Wired to mains power separately for selective control and potted in epoxy, the magnets really seem to do the job. The video below shows a very thick piece of steel plate cantilevered out over one magnet while having a hole cut; that’s a lot of down force, but the workpiece doesn’t move.

Like the idea of a shop-made vise but would rather go the old-fashioned way? Check out [Make It Extreme]’s laminated bench vise, which also makes an appearance in this video.

Continue reading “Your Work Won’t Move with a Magnetic Drill Press Vise”