Dual Color Extruder With A Single Stepper

February 21, 2014 by Brian Benchoff 18 Comments

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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Hackaday Links: February 9, 2014

February 9, 2014 by Mike Szczys 18 Comments

Here’s a quick tip to extend the usefulness of your multimeter. It’s a set of mini test hooks soldered to alligator clips with a short hunk of stranded wire in between. You can buy mini test hooks that go right on the metal probes of your meter, but the weight and bulk of the meter probes and cords sometimes get in the way. This rig allows more flexibility because of that wire.

Staying on the theme of test equipment tips, here’s a simple way to make a Y-connector for logic analyzers. [Thomas] uses a dual-row pin header, shorting each pair of pins so that both rows are connected. When this is plugged into a pin socket it leave two pins for connecting your test equipment and the rest of the project hardware.

After seeing our feature of a 3-wire Character LCD [Chad] wrote in to mention he built a 1-wire version using an ATmega328.

If you’re going to be in Anaheim this week you can stop by the ATX-West expo and see a 3D printer with a 1m x 1m x 0.5m printing area. [Thanks Martin]

Speaking of 3D printers, here’s a big delta robot (seven feet tall) outfitted for alternative material printing. It’s printing a CT scan of ribs and a heart in hot glue. This seems to be a popular material for more artistic uses. We just saw a hexapod which deposits hot glue as it roams.

The weaponized quadcopter post from Tuesday was a controversial one. The really bad part of it was the laser, which strapped to anything is extremely dangerous. But the other hack may have just been poorly executed. Hackaday alum [Jeremy Cook] wrote in to mention that fireworks and quadcopters can be used more responsibly. He strapped a sparkler to his quadro and used it to make light graffiti. You may remember that [Jeremy] wrote an introduction to light graffiti for us back in November.

FaBrickation: Combining Lego And 3D Printing

January 28, 2014 by Eric Evenchick 29 Comments

While 3D printing gives you the ability to fabricate completely custom parts, it does have some drawbacks. One issue is the time and cost of printing large volumes. Often these structures are simple, and do not require completely custom design.

This is where the faBrickation system comes in. It allows you to combine 3D printed parts with off the shelf LEGO bricks. The CAD tool that lets you ‘Legofy’ a design. It creates directions on how to assemble the LEGO parts, and exports STL files for the parts to be 3D printed. These custom bricks snap into the LEGO structure.

In their demo, a head mounted display is built in 67 minutes. The same design would have taken over 14 hours to 3D print. As the design is changed, LEGO blocks are added and removed seamlessly.

Unfortunately, the tool doesn’t appear to be open source. It will appear for the ACM CHI Conference on Human Factors in Computing Systems, so hopefully we will see more in the future. Until then, you can watch the demo after the break.

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3D Printering: Making A Thing In Blender, Part I

January 3, 2014 by Brian Benchoff 52 Comments

In case you weren’t aware, having a 3D printer is nothing like owning a real-life Star Trek replicator. For one, replicators are usually found on Federation starships and not hype trains. Secondly, the details of how replicated objects are designed in the 24th century is an issue completely left unexplored by TNG, and DS9, and only a minor plot point in a few Voyager episodes. Of the most likely possibilities, though, it appears replicated objects are either initially created by ‘scanning’ them with a teleporter, or commanding the ship’s computer to conjure something out of the hologrid.

No, with your own 3D printer, if you want a unique object you actually have to design it yourself. Without a holodeck. Using your hands to move a mouse and keyboard. Savages.

This series of ‘Making a Thing’ tutorials aims to fix that. With this post, we’re taking a look at Blender, an amazing 3D modeling and animation package.

Because we still haven’t figured out the best way to combine multiple blog posts together as a single resource − we’re working on that, though − here’s the links to the previous “Making a Thing” posts:

This list is sure to grow thanks to your suggestions on what 3D modeling software to feature, but for now let’s make a thing in Blender.

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Jello Shot Printer

December 26, 2013 by James Hobson 29 Comments

While inspecting some jello shots for a friend’s upcoming 25th birthday, [Sprite_tm] had an epiphany. What if you could print designs inside the jello shots? He quickly grabbed a syringe and proceeded to inject food dye into one of the jello shots — it worked. Unfortunately, his friend pointed out that it would take far too long to do each jello shot by hand, to which [Sprite] responded:

Never mind that, I’ll just whip up a 3D printer that can make nice figures in the jelly for you.

Classic. The great thing about the hacker-mindset is that you never say no when confronted with a problem!

To achieve this printer, [Sprite_tm] has taken a handful of old CD-ROM drives to create a three axis moving platform. He’s using a forth drive’s ejector assembly to depress a syringe which pushes a concoction of banana liquor, green food colouring and cornstarch through medical tubing to the ink-head. To control it, he’s just using an ATTiny2313 with a mere 2K of memory. It took a bit of fiddling with to find the right flow, but works surprisingly well. Stick around after the break to see its printing capabilities.

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Compliant Robot Gripper Won’t Scramble Your Eggs

December 3, 2013 by Adam Fabio 24 Comments

[Chiprobot] has created an amazing compliant gripper. Designing robot hands (or end effectors) can be a perilous task. It is easy to give robots big, good, strong hands. Strong grippers have to be controlled by sensors. However, sensors can’t always be relied upon to ensure those hands don’t crush anything they touch. Hardware fails, software has bugs. Sometimes the best solution is a clever mechanical design, one which ensures a gripper will conform to the object it is gripping. We’ve seen “jamming” grippers before. (so named for their use of a granular substance which jams around the object being gripped).

[Chiprobot’s] gripper is something entirely different. He designed his gripper in blender, and printed it out with his Ultimaker 3D printer. The material is flexible PLA. Three plastic “fingers” wrap around the object being gripped. The fingers are made up of two strips of printed plastic connected by wire linkages. The flexible plastic of the fingers create a leaf spring design. The fingers are attached to a linear actuator at the center point of the gripper. The linear actuator itself is another great hack. [Chiprobot] created it from a servo and an empty glue stick. As the linear actuator is pulled in, the fingers pull around any object in their grip. The end result is a grip strong enough to hold an egg while shaking it, but not strong enough to break the egg.

We would like to see the gripper gripping other objects, as eggs can be surprisingly strong. We’ve all seen the physics trick where squeezing an egg with bare hands doesn’t break it, yet squeezing an egg while wearing a ring causes it to crack much… like an egg.

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RepRap Wally Can Print Larger Versions Of Itself

October 12, 2013 by James Hobson 10 Comments

SCARA based 3D printers seem to be all the rage these days, and with good reason. This RepRap Wally doesn’t use any linear rods or timing belts — in fact, it can even print larger versions of itself with each iteration! Well, minus the electronics of course.

It was first spotted out in the wild at the NYC Makerfaire, and looks to be a pretty slick design. Using fully 3D printed limbs, the steppers move the arms using a fishing line. To reduce the load on the joints, a bowden extruder is also used. The really cool part of this is the z-axis, it uses a 4-bar linkage to stay level, but because of this, it also moves along an arc in the y-axis as it raises or lowers. This is accounted for in the firmware — otherwise you’d have some rather interesting curved prints!

Stick around after the break to see it in action, it’s a nice change to watch from the standard gantry style printers.

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