The Effects of Color on Material Properties of 3D Printed Components

The strength of object printed on filament-based 3D printers varies by the plastic used, the G-code used by the printer, the percent infill, and even the temperature the plastic was extruded at. Everything, it seems, has an effect on the strength of 3D printed parts, but does the color of filament have an effect on the stress and strain a plastic part it can withstand? [Joshua M. Pearce] set out to answer that question in one of his most recent papers.

The methods section of the paper is about what you would expect for someone investigating the strength of parts printed on a RepRap. A Lulzbot TAZ 4 was used, along with natural, white, black, silver, and blue 3mm PLA filament. All parts were printed at 190°C with a 60°C heated bed.

The printed parts demonstrated yet again that a RepRap can produce parts that are at least equal in material strength to those produced by a proprietary 3D printer. But what about a difference in the strength among different colors? While there wasn’t a significant variation in the Young’s modulus of parts printed in different colors, there was a significant variation of the crystallization of differently colored printed parts, with white PLA producing the largest percent crystallinity, followed by blue, grey, black, and finally natural PLA. This crystallinity of a printed part can affect the tensile properties of a printed part, but [Pearce] found the extrusion temperature also has a large effect on the percentage of crystallinity.

3D Printing Has Evolved Two Filament Standards

We’re far beyond the heyday of the RepRap project, and the Hackaday tip line isn’t seeing multiple Kickstarters for 3D printers every week. In a way, this is a bit of a loss. The rapid evolution of the low-cost 3D printer seen in the first half of this decade will never be matched, and from now on we’ll only see incremental improvements instead of the revolutionary steps taken by the first Prusa, the first Printrbot, and even the Makerbot Replicator.

This doesn’t mean everything is standardized. There’s still enough room for arguing over deltas versus Cartesians, beds moving on the Y axis versus moving along the Z, and a host of other details that make the current crop of printers so diverse. One of these small arguments is especially interesting: the diameter of the filament. Today, you can get any type of plastic you want, in any color, in two sizes: 1.75 and 3mm. If you think about it, it’s bizarre. Why on Earth would filament manufacturers, hot end fabricators, and even printer manufacturers decide to support two different varieties of the same consumable? The answer is a mix of a historical choice, engineering tradeoffs, and an absolutely arbitrary consequence of what 3D printers actually do.

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The Most Self-Replicating RepRap Yet

The goal of the RepRap project was always a machine that could replicate itself. The project began with the RepRap Darwin, a machine with a frame made nearly entirely of threaded rods, and progressed to the Mendel, with a slightly higher proportion of printed parts. Around 2011, the goal of self-replication fell by the wayside after some money was thrown around. The goal now, it seems, is to create the 3D printer with the best profit margins. That doesn’t mean there still isn’t a small contingent of RepRappers out there trying to improve the status quo and create a printer that can truly self-replicate. [Revar] is one of those tinkerers, and he has just released the RepRap Snappy, a snap-together 3D printer built nearly entirely out of 3D printed parts.

Other 3D printers designed around the idea of self-replication, like the RepRap Morgan and the Simpson family of printers, use strange kinematics. The reason for this is that Cartesian bots can’t print up to the limits of their frame, yet self-replication requires all parts be replicated at the same scale.

[Revar] is setting a new tack in the problem of printer self-replication and is joining parts together with snap fit connectors. The entire frame of the Snappy printer is built out of small parts that interlock to form larger units.

Another of the tricks up [Revar]’s scheme is reducing the number of ‘vitamins’ or parts that cannot be 3D printed. This includes belts, motors, screws, and electronics. You can’t really print machine screws yet, but [Revar] did manage to eliminate some belts and bearings. He’s using a rack and pinion system, all made with printed parts. It’s a technique that hasn’t been seen before, but it does seem to work rather well.

[Revar] has made all the files for the printed parts available in his repository. If you have enough filament, these files are enough to print 73% of the RepRap Snappy.

Thanks [Matt] for sending this one in. Video below.

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Sinterit Pulls SLS 3D Printer Entry Level Price Down to Just $8k

Almost exactly two years ago, news of a great revolution in 3D printing carried itself through blogs and tech columns. Patents were expiring, and soon the ‘squirting filament’ printers would be overtaken by a vastly better method: selective laser sintering. In the last two years, the market has been markedly silent on the possibilities of SLS technology, until now, at least. Today, Sinterit is launching their first printer. It’s an SLS printer that builds objects by fusing nylon powder with a laser, producing things with much better quality than filament-based printers.

The Sinterit Lisa is a true laser sintering printer, able to create objects by blasting nylon powder with a 5W laser diode. Inside this box that’s about the same size as a laser printer is a CoreXY mechanism to move the laser diode around, heated pistons, cylinders, feed bed and print bed for keeping the print volume at the right temperature and the top layer perfectly flat. The layer thickness of the printer goes down to 0.06 mm, and the maximum print size is 13 x 17 x 13 cm. Material choice is, for now, limited to black PA12 nylon but other materials are being tested.

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Hello RAMPS, meet ESP8266

The proliferation of  DIY 3D printers has been helped in large measure by the awesome open-source RepRap project. A major part of this project is the RAMPS board – a single control board / shield to which all of the other parts of the printer can be easily hooked up. A USB connection to a computer is the usual link of choice, unless the RAMPS board has the SD-Card option to allow the 3D printer to operate untethered. [Chetan Patil] from CreatorBot built a breakout board to help attach either the ESP8266 WiFi or the HC-05 Bluetooth module to the Aux-1 header on the RAMPS board. This lets him stream G-code to the printer and allow remote control and monitoring.

While the cheap ESP8266 modules are the current flavor of the season with Hackers, getting them to work can be quite a hair tearing exercise. So [Chetan] did some hacking to figure out the tool chain for developing on the ESP module and found that LUA API from NodeMcu would be a good start. The breakout board is nothing more than a few headers for the ESP8266, the HC-05 and the Aux-1 connections, with a few resistors, a switch to set boot loader mode and a 3.3V regulator. If you’re new to the ESP8266, use this quick, handy, guide by [Peter Jennings] to get started with the NodeMCU and Lualoader. [Chetan]’s code for flashing on the ESP8266, along with the Eagle board design files are available via his Github repo. Just flash the code to the ESP8266 and you’re ready to go.

One gotcha to be aware of is to plug in the ESP module after the printer has booted up. Otherwise the initial communication from the ESP module causes the printer to lock up. We are sure this is something that can be taken care of with an improved breakout board design. Maybe use a digital signal from the Arduino Mega on the RAMPS board to keep the ESP module disabled for a while during start up, perhaps? The video after the break gives a short overview of the hack.

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Wood & Glue RepStrap Works Surprisingly Well

Even with the cost of 3D Printers continually falling, entering the hobby still requires a significant investment. [Skeat] had some typical 3D Printer components available but didn’t have access to a printer for making the ever-so-common frame parts of typical RepRap designs.

glue rep strap [Skeat’s] plan was to cobble together a printer just good enough to print out parts for another, more robust one. The frame is made from wood, a very inexpensive and available material. The frame is not screwed together and doesn’t have any alignment tabs, it’s just hand cut pieces glued together. Each portion of the frame is laid out, aligned with a carpenter’s square and then glued together. This design and assembly method was intentional as [Skeat] didn’t have access to any precision tools. He stated that the only parts of the frame that had to be somewhat precise were the motor mount holes. The assembly process is well documented to aid anyone else looking to make something similar.

In addition to the wooden frame, all of the components are glued in place. That includes the bearings, rods, limit switches and even the Z axis motor! After seeing the photos of this printer, it would be easy to dismiss it as a poor performer. The below video shows that this printer’s print quality can keep up with any hobby level machine available. We wonder if [Skeat] is rethinking making another since this one works so well.

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MapleMaker 3D Printer is As Printable as They Get

The term RepRap is fairly common and gets thrown around too often when generally talking about DIY 3D Printers. We must remember that the intent of the RepRap project “…is about making self-replicating machines…” and of course “…making them freely available for the benefit of everyone…“.

[MiniMadRyan] has recently designed a printer that could be considered the embodiment of the RepRap philosophy. He’s calling it the MapleMaker Mini V2. An extremely high percentage of the parts required to build this printer are, in fact, printable themselves. The frame pieces are printed, all of which can be printed on the printer thanks to the 6x8x6 inches print volume. The overall design is aesthetically pleasing, resembling that of a Lulzbot Mini.

The MapleMaker Mini V2 is self-replicating. The other part of the RepRap goal is to be free to the community. The design files are available on YouMagine and the assembly manual is better than those provided by most commercial companies. So if you’re looking to build a printer, be sure to add this one to your short list!