MakerBot Files Patents, Internet Goes Crazy

patent

In the past month, a few patent applications from MakerBot were published, and like everything tangentially related to the prodigal son of the 3D printer world, the Internet arose in a clamor that would be comparable only to news that grumpy cat has died. That’s just an analogy, by the way. Grumpy cat is fine.

The first patent, titled, Three-dimensional printer with force detection was filed on October 29th, 2013. It describes a 3D printer with a sensor coupled to the hot end able to sense a contact force between the nozzle and build plate. It’s a rather clever idea that will allow any 3D printer to perform software calibration of the build plate, ensuring everything is printed on a nice, level surface. Interestingly, [Steve Graber] posted an extremely similar design of a bed leveling probe on October 6th, 2013. In [Steve]‘s video, you can see his bed level probe doing just about everything the MakerBot patent claims, all while being uploaded to YouTube before the patent application.

When it rains it pours, and the Quick-release extruder patent application, filed on October 28, 2013, bears this out. It claims an extruder that includes, “a bistable lever including a mechanical linkage to the bearing, the bearing engaged with the drive gear when the bistable lever is in a first position and the bearing disengaged from the drive gear when the bistable lever is in a second position.” Simple enough, a lever with two positions, where one presses a bearing against a drive gear, and the other position disengages the bearing from a drive gear. Here’s something that was published on Thingiverse in 2011 that does the same thing. Hugely famous RepRap contributor [whosawhatsis] has weighed in on this as well.

It is important to note that these are patent applications. Nothing has been patented yet. The US Patent and Trademark Office does seem to have a lot of rubber stamps these days, so what is the average Internet denizen to do? Here are easy to follow, step-by-step instructions on how to notify the USPTO of prior art. Remember, just because prior art does not completely invalidate a patent application’s claims doesn’t mean you shouldn’t send it in. It is a patent examiner’s job to review the prior art.

So there you go. MakerBot applies for patents, people complain, but not to the USPTO. Highly relevant video and transcription below.

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Blobless Printing With Velocity Extrusion

velocity

The current crop of 3D printers are technically four-axis machines, with three axes of movement and a fourth for the position of the filament. [Bas] had an entirely different idea – why not link the speed of the extruder to the speed of the nozzle? It turns out this technique gives you more ‘plasticy-looking’ prints and a vast reduction in blobbiness.

[Baz] has been working with LinuxCNC, a BeagleBone Black and the BeBoPr-Bridge cape, and there’s been a lot of development with that system in turning many straight lines into one smooth arc. This led him to adjusting the flow rate of a nozzle while the printer is running, but this is difficult if the extrusion is controlled by position as in a traditional printer setup. A new configuration was in order.

What [Baz] ended up with is a config that calculated the speed of the extruder based on the speed the nozzle is moving over the print surface. This gave him the ability to add live nozzle pressure adjustment, and as a result, a near complete disappearance of the little blobs that appear at the start of each layer.

For a well calibrated machine, it’s only a small difference between the ‘normal’ and ‘velocity’ methods of controlling an extrusion rate. It’s a noticeable difference, though, and one that vastly improves the visual quality of a print.

 

Dual Color Extruder With A Single Stepper

extruder

Once you have a 3D printer able to build a few objects in a single color, the next logical upgrade is a dual extruder. A dual extruder allows for multiple color prints, and by adding a dissolvable filament, the ability to print object that would otherwise be impossible. Fitting a dual extruder on an existing 3D printer presents a problem: simply by using a second stepper motor, you reduce the print area of your printer significantly. That’s the problem Dglass 3D aims to solve with their extruder. It’s a dual filament extruder that uses only one stepper motor and takes up less space than some other single filament extruders.

This isn’t the first time the guys at Dglass 3D have tried Kickstarting a dual filament extruder; last year we saw a very similar mechanism that used a single stepper motor to feed two filaments. This older model lacked retraction, though, meaning two colored prints would range somewhere between messy, inaccurate, to impossible.

The new extruder uses a servo to ‘latch’ the filament and drive it into the hot end. This means retraction of the filament is possible and from the sample prints with this extruder, the results look pretty good.

Below You’ll see a few video demos of the dual color/retraction extruder printing an object in black and white filaments at the same time. It’s very cool, and with the addition of a dissolvable filament means very complex objects can be printed very easily.

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[Ben Heck] Builds The Ultimate Glue Gun

glue

For how many can be found on the workbenches and in the toolboxes of makers and hackers the world over, finding a glue gun that does more than just heat up and drip glue everywhere can be a challenge. [Ben Heck] finally solved this problem with a hot glue gun that’s more like an extruder from a 3D printer than a piece of junk you can pick up at Walmart for a few dollars.

By far, the most difficult part of this project was the glue stick extruder. For this, [Ben] used a DC motor with a two-stage planetary gear system. This drives a homemade hobbed bolt, just like the extruder in 99% of 3D printers. The glue stick is wedged up against the hobbed bolt with a few 3D printed parts and a spring making for a very compact glue stick extruder.

The electronics are a small AVR board [Ben] made for a previous episode, a thermistor attached to the hot end of the glue gun, a solid state relay for the heater, and analog controls for speed and temperature settings. After finishing the mechanics and electronics, [Ben] took everything apart and put it back together in a glue gun-shaped object.

The finished product is actually pretty nice. It lays down constistant beads of hot glue and thanks to a little bit of motor retraction won’t drip.

You can check out both parts of [Ben]‘s build below.

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A Really Big Extruder For Exotic Filaments

extruder

Even with ABS, PLA, Nylon, HIPS, and a bunch of Taulman filaments, the world of 3D printers is missing out on a great supply of spools of plastic filament. Plastic welding rod is available from just about every plastics supplier, and in more variety than even the most well-stocked filament web shop.

This Kickstarter hopes to put all those exotic plastic welding rods to good use. Instead of being designed to only use 1.75 and 3mm filaments, this guy will extrude welding rods up to 4.76mm in diameter. This opens the door for 3D printed objects made out of PDPF, PVC, Polypropylene, Polyethylene and other high molecular weight plastics.

Because these welding rods are much bigger than the usual plastic filament, this extruder also has the option for a very beefy NEMA 23 motor. It’s the perfect solution if you’re planning on building a homebrew ludicrous-sized printer, or you just to show off just how awesome you are.

DIY Filament: The Filabot Wee

filabotwee

Now there’s yet another option for making your own 3D printer filament: the Filabot Wee. It looks like their once open source model that they pulled from Thinigiverse earlier this year has received a significant makeover, though we aren’t sure what parts may have changed. (EDIT: Filabot says the Wee is still open source, and that once they’ve updated the files they will be available again.)

As you would expect, the Wee has a PID temperature controller and is capable of extruding both ABS and PLA pellets into either 1.75mm or 3mm-diameter filament. Speed varies depending on materials and thickness, but can reach 5 to 20 inches per minute of filament extrusion. Though the Filabot gang is selling the extruder as a kit, you can probably save a few bucks if you have access to a laser cutter and some other basic materials.

You should expect to spend more for Filabot parts ($649) than you would for the original Lyman extruder, though perhaps a more fair comparison would be the new third version of the Lyman extruder, whose bill of materials approaches $900. Considering Lyman’s recent comments that indicate an extrusion rate of 40-50 inches per minute, the extra bucks may be worth it. You can check out a demonstration video of the Filabot Wee after the break.

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A deck screw extruder

deck

A lot of great ideas happen in the middle of the night, and for [Werner] it’s no different. One night he came up with an idea for a new 3D printer extruder, and after a very basic prototype, we’d have to say he might be on to something. It’s basically a deck screw acting as a worm gear to drive filament, but this simple idea has a lot of really cool advantages.

There are two really interesting features of this extruder, should [Werner] ever decide to flesh out his idea into a real prototype. First, the stepper motor for this extruder can be extremely small and mounted directly above the extruder. This opens up the doors to easily creating multi-extrusion printers that can handle more than one filament. Secondly, using a deck screw as a worm gear means there is a huge area of contact between the plastic filament and the driver gear.

Whereas the usual extruder setup only makes contact with the plastic filament along one or two splines of a hobbed bolt, [Werner]‘s design drives the filament along the entire length of the deck screw worm gear. This could easily translate into much more accurate extrusion without all the fiddling around with springs and hobbed bolts today’s extruders have.

In any event, it’s a very interesting idea, and we’d love to see [Werner] or someone else make a functioning extruder with this design.

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