Polar Pen Plotter Draws Huge Images Very Slowly

November 17, 2011 by Brian Benchoff 7 Comments

[Euphy] just posted an Instructable of his Polargraph drawing machine that’s able to draw huge images slower than molasses in November. The plotter only uses two stepper motors to control the position of the pen and can be made nearly entirely from salvaged parts – [Euphy] built his for just about £150.

The Polargraph uses two stepper motor on the top corners of a large, flat surface. A weighted pen carriage is attached to both motors with beaded cord that’s often seen in window blinds. By controlling the distance from the carriage to each motor, the position of the pen can be precisely controlled. It’s not a very fast way of drawing an image (check out the real-time video), but it sure is interesting to watch.

There have been a few other rope-and-chain plotters, like Der Kritzler and Hektor. [Euphy]’s work is the is one of the best documented builds we’ve seen, and he’s also put up the code and a website.

We really could have used [Euphy]’s plotter when we wanted to draw some whiteboard art. While we’re out dumpster diving for some small stepper motors, check out the time-lapse video of the Polargraph after the break.

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A Technique To Avoid Warping On Large 3D Prints

November 15, 2011 by Mike Szczys 42 Comments

[Jamie Mantzel] figured out his own way of 3D printing large objects without fear of warping. First a bit of background information. When using a 3D extrusion printer like the RepRap or Makerbot, prints that span a large area tend to warp. That’s because these printers lay down one thin layer of plastic at a time. If the first layer cools too much, it will shrink a bit before the next layer is laid down. As that second layer cools it pulls the part toward the center, eventually bowing the part which causes it to hit the extruder head.

After having several prints encounter this issue [Jamie] decided to alter his design so that it wouldn’t cause these stresses. The first thing that he did was to add alternating voids to a layer between the raft and the actual part. You can see these as notches on the bottom the piece pictured above. This takes care of the initial stresses from the first layer. Next, he adds holes wherever he can in the main body of the part. This is especially important on the edges of the piece where the warping forces will be the greatest.

He also moved the starting position of the bed closer to the extruder head. His hope is that this will help the raft bond better, and resist pulling away from the bed during printing.

See his video explanation of his adventure after the break.

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Build Your Own Stereolithographic 3D Printer

November 14, 2011 by Mike Szczys 26 Comments

[Andy’s] 3D printer build uses lasers to create objects from goo. The Stereolithographic process uses resin that is cured by UV light to create the finished product. A single laser mounted to a CNC gantry is able to precisely target a point on the surface of the resin to begin the printing process. As the layers are built up, the stage, which is mounted on the Z axis, slowly sinks into the resin vat. So basically you’re printing from the bottom up but the laser never moves up or down. There’s a time-compressed video of an object being printed embedded after the break. It illustrates the process better than we can describe it.

We think [Andy] really went all out with his write-up of the build process. The quality he achieves in his prints is quite excellent, but you must consider the cost versus an extrusion-based 3D printer. One liter of the UV resin he prints from can cost over $200.

If this sounds familiar it’s because we got a sneak peek at it back when we looked in on his Delta robot work.

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Half-tone CNC With Man-powered Z Axis

November 14, 2011 by Mike Szczys 10 Comments

We think this is an intriguing take on half-tone art. It’s a CNC machine that uses an Arduino and two stepper motors to draw on a paper-covered drum. But you’re not just going to set it and forget it. To simplify the device, the Z-axis is not mechanized, but requires the dexterous opposing digit of a person to actuate.

The first prototype used a frame cut from plywood, but the developers moved to some attractive laser-cut Lexan for the final version. The rotating drum was inspired by observing the off-set printing process. It greatly simplifies the build when compared to a flat CNC bed. But including a Z-axis solution that could account for differently sized dots really opens a can of worms. Because of this, the choice was made not to automate that task, but to leave it up to the user. A clickable Sharpie does the marking. When the pen is in place, you click the plunger to hold the felt tip against the paper until a dot of the appropriate size has leeched onto the paper.

It’s not a bad solution to the problem. Especially if you don’t have the high-end milling equipment necessary to do this on a piece of plywood.

[Thanks Dron]

$150 CNC Mill Is A Tad Slow But Very Solid

November 11, 2011 by Mike Nathan 19 Comments

diy-150-cnc-mill

Like just about everyone else out there, [Adam] thinks that CNC machines are pretty cool – so cool that he decided to build one of his own from scratch.

The CNC machine was constructed mostly out of MDF and scrap wood, with drawer slides used for smooth gantry movement. An off-brand rotary tool was used to do the actual cutting, and [Adam] picked up a few Sparkfun stepper motors to drive the machine.

The assembly was completed without too much trouble, but [Adam] says that programming the mill was a long and frustrating process. Cutting was rough and not very accurate at first, but little by little he got things working pretty well. As you can see in the video below, while the cuts look great, improvement came at the expense of speed. He says that the machine could use a redesign to speed it up, which he’ll get around to if some free time comes his way.

It’s not the absolute cheapest CNC build we’ve seen, it’s pretty darn close. With a few tweaks, it could definitely be a solid budget-friendly contender.

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This Panavise Jr. Speed Winder Should Be In Every Maker’s Toolbox

November 7, 2011 by Mike Nathan 34 Comments

panavise-jr-power-winder

Like many makers, [Chris] has a Panavise Jr. on his workbench that he uses for just about everything. The tiny vise is great for all sorts of tasks, and is often considered an indispensable tool. The only problem with the vise is the amount of time it takes to open and close the thing.

[Chris] estimates that it takes somewhere between 2 and 3 million turns of the crank to move the vise’s jaws from fully open to the fully closed position. He figured that his drill is far better at mindlessly turning circles than he is, so he sat down and designed a bit in Google Sketchup to spin the vise’s crank knob.

He fired up his MakerBot and printed out his first “Speed Winder” drill bit. It was decent, but he thought it could be better. After a handful of revisions, he was finally happy with the results. He says it works great, and has posted the model on Thingiverse so that everyone can print one of their own.

Continue reading to see how [Chris] created the bit along with how much time this thing saves him. Continue reading “This Panavise Jr. Speed Winder Should Be In Every Maker’s Toolbox” →

4Track Robot Gets Around With Ease

November 6, 2011 by Mike Nathan 8 Comments

4track-robot

[Jon] has been developing a slick little RC robot in bits and pieces over the last year or so, which can constructed by anyone with access to a 3D printer. Servos and electronics aside, the entire thing can be put together in short order using the plans he posted on Thingiverse.

The robot makes use of four “caterpillar” type bots, which are all connected via a central frame. Once [Jon] had the general design for a single caterpillar bot down, he moved forward to create the robot you see above. His friend [Julián] lent a hand in the form of electronics and code, which allows the robot to be driven using a standard USB gamepad.

As you can see in the video below, the robot gets around nicely, climbing over obstacles with relative ease. While it is a bit loud, [Jon] says that’s due to the undersized servos they happen to be using at the moment. We think it looks great so far, but [Jon] already has plans to beef up the motors and add wireless control in the near future – we can’t wait to see it then!

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