www.3ders.org

Feb. 23, 2015 | By Alec

Once again talented hackers are proving that open-source development is the quickest and most effective way forward. Not only does it ensure that technology becomes available to as many people as possible, it also opens the doors to the quickest and most productive growth and expansion of technological knowledge. This time, it's the two brothers behind Spanish open source developers Diyouware.com who are leading the way, having developed the TwinTeeth multi-purpose PCB manufacturing machine that definitely deserves being called a mini-factory.

For those of you who’ve never heard of Diyouware.com (do-it-yourself-ware), it’s an interesting blog about robotics, mechatronics and software development that. Staying true to the spirit of open-source design, they usually share all designs and files for their interesting hardware constructions for free. Just six weeks ago, we reported on their PCB printer with a Blu-Ray pickup which can be used to print circuit boards. And now, it looks like they’ve expanded on that, creating a PCB mini-factory that is part RepRap 3D printer, part laser engraver, part CNC miller and much more.

The whole setup with various tool heads in front.

 

As the duo explains on their blog, the development of the TwinTeeth has arisen out of their struggles with the mechanical vibrations and belt resonances during their previous project. ‘When we began TwinTeeh project we were afraid of not finding a free-vibration mechanical designing because we tried almost everything to avoid vibrations in DiyouPCB. It is very important to avoid any kind of vibration when drawing with a laser because the beam is very fine (aprox. 620 nm) and any tiny motion would move it and distort the drawing.’

Fortunately, they’ve since come up with a some solutions. Firstly, the belt resonances can be, they discovered, avoided using lead-screws. ‘This was the base of our new designing. But we didn’t have a clear idea about how to eliminate other kind of vibrations, mainly produced by motors and linear bearings. Inspiration arose from my twin babies when they tried to brush their teeth for the first time. One of them was brushing his teeth in the normal way but the other one thought it was easier to move the head instead the brush. Why not?’ They explained.

Applying that same principle to their newest build, the TwinTeeth (you now also know why it’s called that) instead moves the construction bed, rather than the tool head, in a sort of reverse Delta printer way. ‘Fixing the tool on the top of the robot has other benefits: we can interchange it [with other tool heads] very easily because it is not attached to any moveable part. Also because the robot doesn’t have to move wirings, filaments, heavy loads, cable chains, etc.,’ they added.

The Diyouware TwinTeeth PCB maker thus with interchangeable tool heads which enables it to take over just about every fabrication stage in the process of PCB building. Its simply a matter of interchanging the various heads which, the brothers assure us, is very easy to do. This should enable you to easily make PCBs the size of an Arduino shield at home. In fact, it includes the following functions:

• UV Laser photoengraving on sensitive film or pre-sensitized boards using an ultraviolet laser.
• Drilling vias and holes using any mini-rotary tool like Dremel® or Proxxon®.
• Dispensing solder paste with precision on SMD PCB pads.
• Plotting circuits with a permanent pen-maker (if you prefer this method).
• 3D printing knobs, casings, front-panels, even print circuits with conductive filament, or make circuits supports.
• Milling/Carving soft materials or etching PCB copper with a v-bit (if you prefer this etching method).

Check out the TwinTeeth PCB mini factory in action here.

But of course, as this is open source and completely revolving around replaceable tool heads, you can theoretically develop any type of toolhead you’re looking for. The Twinteeth’s potential is thus enormous, provided you can keep things limited to the machine’s relatively small working space of 70x80x60mm ‘We reduced it considerably to an “Arduino™ shield-size” because we preferred to do something small but precise,’ the brothers explain. ‘We rarely create big circuit boards and reducing the working area has some benefits: the robot is cheaper, more precise, more robust, smaller and more manageable. However, it’s scalable, so you can make it bigger if you want.’

The TwinTeeth with a drill toolhead in place.

 

The machine itself runs on the commonly used combination of Arduino™ Mega + RAMPS 1.4 + A4988 Motor Drivers. It uses a custom-made software package as well, including the TwinTeeth Firmware which supports the various tools, including the 3D printer, as well as an supposedly very easy to use console especially designed for a multi-tool system with a lot of functions (see their blog post for the full list). They’ve also included Eagle Cadsoft, a freeware version for non-commercial CAD design. ‘It easily generates the postscript, drilling and solder paste dispensing files which TwinTeeth uses to make the circuits,’ they explain. This means that their build supports G-Code, postscript and BMP files, though you do need to rely on your common slicing software (such as Slic3r).

The small build area itself is moved around by three Nema 17 motors, which enable speeds in the range of 1200-1500mm/minute, making this a very efficient machine as well. The TwinTeeth logically also includes a precision aluminium fixture bed, to ensure it remains perfectly aligned throughout your projects. For the laser, the brothers are again opting for a PHR-803T optical pickup with a wavelength of 405nm, which is only 0.04m wide when focussed.

But its 3D printing function – obviously the most important of all – is nothing to snuff at either. They have relied on a combination that is relatively common amongst RepRap users: a mix of Greg’s Extruder and a J-Head hot-end. ‘The extruder, as the rest of ToolHeads, is connected to the DB15 bus which includes signal lines to control the stepper-motor, the hot-end resistor and the thermistor, they explain.

This setup enables FDM 3D printing of both PLA and ABS filaments at 1,75 mm through an extrusion head of 0,35 mm. Its quality, they assure us, is comparable or better than that of a typical desktop 3D printer, as its fixed extrusion head should ensure very high levels of precision. Their Management Console also already includes calibration, filament-feeding and extrusion controlling functions.

The TwinTeeth management console for 3D printing.

 

The TwinTeeth PCB mini-factory thus seems to feature a very capable FDM 3D printing option, though they brothers add that its potential can be extended to other functions as well. In fact, as part of a follow-up project they are considering developing a SLA 3D printing tool head as well. ‘We already drafted a blue-print using the Laser ToolHead. The main benefit in respect similar to technologies is that the laser will be very close to the resin (less than 10mm) and perfectly focused in a very tiny and precise spot,’ they said, adding that they’ve already heard of a resin 3D printing setup that runs on a PHR803-T picku. ‘So it’s possible to do it.’

And, almost as an afterthought, they suggest that their build can even be extended to function as a biopolymer 3D printer as well. ‘It seems easy: just add a UV photo-initiator to any hydro gel and 3D print on it with the UV laser beam. The benefit of using the TwinTeeth could be the precision, because the laser beam is perfectly focused and close to the hydro gel surface.’ While that is so far mere speculation, they invite scientists interesting in expanding on this bioprinting setup to contact them through their website.

All in all, the TwinTeeth is thus a very impressive build that takes RepRap 3D printing above and beyond its normal functions. If you’re looking to build this open source work of art for yourself, you can find all the necessary files here, though you probably don’t need to be reminded of the sheer scale that this project will entail. The brothers are also still working on a construction tutorial, so keep an eye open for it.

 

 

Posted in 3D Printers

 

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