First Look: Pegasus Touch Desktop SLA 3D Printer

10/9/2014

Affordable Desktop Stereolithography

I recently purchased a FSL3D Pegasus Touch 3D printer and have had some small success in getting it to operate. Unlike most desktop “prosumer” 3D printers, which use the FDM/FFF extruded plastic technology, the Pegasus Touch uses a process called stereolithography (SLA). Stereolithography was developed in the mid-80’s by Chuck Hull, who went on to found 3D Systems. Stereolithography involves using ultraviolet light to cure a photosensitive resin in thin layers. As with FDM/FFF, the layers are built up to form the finished object.

Until relatively recently, SLA printing was an expensive proposition. Lower-end machines cost $100,000, and the resin could be more than $200 per liter. Recently, firms have worked to produce smaller, more affordable SLA printers. One of the better-known Kickerstarter success stories was FormLabs, developer of the Form1 SLA printer. Their funding target was $100,000; the campaign raised nearly $3 million.

I came close to going with the Form1. Instead, I opted for the Pegasus Touch, a newer model. It is produced by Las Vegas-based Full Spectrum Laser, a company that has been making laser cutters and related products for several years before deciding to jump into 3D printing. Also, the Pegasus Touch boasts a 7″ x 7″ x 9″ build volume, considerably larger than the Form1’s 5.9″ x 5.9″ x  6.5″ volume. I’m a sucker for a large build volume.

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FSL3D’s Pegasus Touch 3D Printer

Out of the Box at Last

I didn’t get in on the Pegasus Touch Kickstarter campaign, but did get a “pre-order” in for their early production models. This meant a 3-month wait time. (This was one of the other reasons I was not going for the Form 1; they had a 5- or 6-month backlog when I was looking into their printer.) Of course, there was another month of delays, but this was not unexpected. Finally, I got the shipment and got it set up. First thing I noticed: there is no power switch. Seriously? The user manual instructs the user to turn the power on by “plug[ging in] the DC barrel connector into the power port on the machine.” I have to admit to being somewhat mystified by the engineering decision to not include a power switch. Using the AC adapter connector to turn the machine on and off produces a visible spark, so don’t use this printer near flammable materials or exposed circuit boards. Hopefully, FSL3D will include a power switch in the next design iteration.

I will make two disclaimers at this point. The first is that I know that getting a new and complex piece of 3D printing equipment to function properly takes time and patience. The second is that while I have the time, I don’t have the patience, and can be a terrible pain in the keister about the printer not working properly. Most of the Makerbot support department will attest to this, as will all of the FSL3D support department.

So began my back-and-forth with the company’s support department. This is one area where FSL3D could also use some improvement. Most of the people I talked to were very nice, but they seemed really overextended. Both Makerbot and FormLabs have well-deserved reputations for excellent customer support – FSL3D would do well to try and learn a few lessons on how to structure their support department. The biggest problem was – for reasons that have never been determined – all of their responses to my email support inquiries never showed up in my inbox. The workaround for this ended up being using a Gmail account, but it did get my blood pressure elevated when it seemed my concerns were being ignored. Also, there are some very important setup tips for leveling and homing the build plate that are not included in the User Manual. These exist solely as videos on the FSL3D website. Seeing as these are very important steps for properly setting up the printer, they should be included in the written documentation. Hopefully, this will be addressed shortly as well.

Photosensitive Resin Goo Blues

Handling the photosensitive resin is one of the biggest challenges of SLA 3D printing. Dealing with the spools of filament used in FFF/FDM printers is simple; not so with SLA resin. First, it’s photosensitive, so it needs to be kept out of direct sunlight and bright artificial light. The yellow-colored plastic cover filters out the UV light that cures the resin, so it can be left in the printer for a long time with no ill effects. Also, the resin is just plain messy to handle. Special care must be taken when dealing with the resin tank inside the printer to avoid spilling or dripping the resin onto the electromechanical innards. Also, the final prints are coated with uncured resin, which also needs to be cleaned off with is0propyl alcohol.

My first print attempt with the Pegasus Touch went awry, as would be expected with a new machine. When I was finally able to communicate with FSL3D’s customer support, I was advised to watch the instructional videos for leveling and homing the build plate. This required removal of the build plate and resin tank, draining the resin into a light-proof bottle, and carefully cleaning the plate and tank with isopropyl alcohol. Transferring the resin from the tank to bottle is messy, and since the resin is rather viscous there is always a loss of material when transferring – and at $120/liter, you want to conserve as much resin as you can.

However, I got the build plate leveled and homed and the resin & tank replaced without too much difficulty, and was able to print one of the typical test print pieces – a detailed chess piece rook.

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First successful print from Pegasus Touch 3D printer

This was printed at the intermediate resolution of 0.05 mm, and the detail was very impressive. Some of the details are hard to see with the clear resin, but it does allow you to see the little spiral staircase inside the model.

I haven’t fully explored all of the capabilities of the proprietary Retina Create slicing software, but it too is fairly impressive. One of the cool features of Retina Create is the ability to edit the supports for the model. Overall, Retina Create is intuitive and easy to use, and I’m looking forward to getting better acquainted with its functionality.

3D Printing Upside Down

Another issue I’ve had with the debugging of the Pegasus Touch has to do with the resin tank itself. The tank is clear acrylic, with a layer of an optically clear silicone compound on the bottom. To build the layers, the build plate lowers into the tank , and for the first layer, the plate needs to be flush with the silicone layer on the bottom of the tank. The UV laser is aimed through the acrylic tank bottom and silicone layer, and cures the resin on the underside of the plate. Then the build plate raises up slightly, and the laser cures the next layer of resin, and so on. The final print comes out hanging upside down from the build plate, like so:

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A rack of rooks hanging from the Pegasus Touch build plate

The problem I ran into is that by not having the plate perfectly leveled and zeroed, the initial layer stuck to the silicone layer instead of the plate. This renders any subsequent attempts to create new layers worthless, as the laser is now just shooting into the layer stuck to the silicone on the bottom of the tank. You must be careful in removing this cured resin from the silicone layer – a lesson I learned the hard way. If care is not taken in removing the cured resin from the bottom, it can tear the silicone layer, which is exactly what I did. Now I’m waiting on a replacement tank, which is currently on back order from FSL3D.

The Verdict

Overall, I’m pleased with the initial experience with the Pegasus Touch printer. Dealing with the resin adds a new layer of complication to printer operation and maintenance, and as I’ve learned care must be taken in handling the resin tank and the silicone layer on the bottom. However, the initial prints I’ve gotten are good-looking and well-detailed, and I’m looking forward to seeing what else the Pegasus Touch is capable of.

FSL3D would do well to beef up their support operations, and overhaul the User Manual to include the important plate leveling and homing procedure. And add a power switch. Overall, the Pegasus Touch seems like a promising device, and I’m looking forward to using it more once the replacement tank arrives. I’ll keep you posted on further developments.

For more information on Tesseract Design’s 3D printing services, please see www.tesseract-design.com/3-d-printing