Figuring out kerf for precision parts

Knowing how much material a laser cutter takes away can be a tricky problem for precision parts, but James Williamson has an answer.

It’s easy to tell when most tools take away material from a cut. A bandsaw cuts a slot the width of its teeth. A table saw cuts a slot the width of its blade. There’s lots of swarf, and powder, and sawdust around telling you things have been cut away. Laser cutters are a bit more subtle.

The amount of material a laser cutter will take away, or kerf, will depend on the speed of the laser cutting, the material, its thickness, and the power of the laser.

James Williamson has come up with a pattern (see above) that he’s cut in a variety of materials on a 40 watt laser cutter. By sliding all the cut pieces to one side of the frame and inserting a shim he’s able to determine the total material lost. Divide that by the number of cuts and you have the material removed by each cut. Clever, nes pas?

Here’s his table of the materials he’s tested:

Material Thickness Cut Speed
(/400)
Cut Power
(/100)
Go
(mm)
No go
(mm)
Average Kerf
(mm)
Acrylic 3mm 6.5 98 1.25 1.30 0.125
Acrylic 5mm 3.5 98 1.30 1.35 0.130
Acrylic 6mm 3 98 1.40 1.45 0.140
Ply 3mm 7 98 2.00 2.05 0.20
Hardboard 3mm 3 98 1.90 1.95 0.19
Mount Board 1.25mm 12 98 2.00 2.05 0.20

For more brilliant laser projects, check out James’ site.

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3D printing complex organic shapes

Use a few free simple programs to turn a scanned skull into a printed masterpiece.

Gian Pablo of Makerbot was a little daunted at first when he was tasked with printing an enormous complex 2/5 scale crocodile skull. He used a CT scanned crocodile skull from the University of Texas Digimorph project. Laser scanned and MRI derived files can be full of junk geometry and self-intersections, but with a few deft repairs you can get most files print ready in less than an hour.

He took his model into the free STL suite Netfabb for some cleanup, scaling, and slicing (this would be the point at which you could take your model into your own Personal Factory to print). Netfabb has a convenient auto-repair script that can handle most basic geometry problems and generate manifold surfaces. He then used Makerbot’s own free program ReplicatorG to generate code for the Makerbot.

After that all that was left was to print the skull in stages, and glue the resulting parts together.

You can read the full details over on Makerbot’s own blog.

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Real world keygen: high security

You may recall my post a few weeks ago about Nirav Patel’s incredible physical keygen project. Well, he’s stepped it up to high security compatible keys in his latest hack.

After spending some time with Schuyler Towne of Open Locksport he discovered his parametric 3d printing process could be applied to more esoteric and high security locks, like the disc detainer lock pictured above.

If you feel like fooling around with some lock picking yourself you could download Nirav’s files off of Thingiverse and get cracking.

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A marvelous automatic scribe from Chris Eckert

Chris Eckert’s sculpture “Auto Scribe” has the patience of a saint, transcribing a medieval bible like a friar of yore.

You may recall a piece we did on Chris Eckert’s automated tattoo machine a few months back. His latest piece “Auto Scribe” is set to be even more breathtaking. (more…)

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The Anywhere Organ

I made a mobile pipe organ out of a recycled church organ and laser cut plywood. Check it out at Figment this weekend!This weekend begins the next phase in a sculpture I’ve been working on for over a year. It’s called the Anywhere Organ, and it rocks. Early in 2010, I ran into a friend from high school who grew up to become a world renowned organ player. He clued me in on the growing trend of churches discarding their organs in favor of digital sound systems.

It seems that with the tuning, maintenance, and cleaning of a full size church organ (sometimes containing over 1000 pipes) the bills can get a little steep. Compound that on the sad fact that pipe organ experts are in short supply and it seems that pipe organs are quickly going the way of the sackbut, the autoharp, and the lute. (more…)

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Real world keygen

A curious hacker creates a program that generates working 3d printed house keys.

Keys are a special, perennial love of the hacking community. With projects like SNEAKEY and Open Locksport getting the huge press they have in the last year, it’s been a fait accompli that someone would create a procedural method for generating real world keys.

All-around hacker Nirav Patel has done just that. His Physical Keygen project combines his Rep-Rap (an open source FDM style 3d printing machine) with code developed in OpenSCAD (an open source 3d modeling script). Using a combination of measurements taken from a few household keys and a reference chart of manufacturers’ key bit charts he developed the program to take some simple information about any key and develop a working model of it in CAD strong enough to turn an ordinary lock. He’s put up all the relevant files for download so you can generate your own keys.

Via Hack-A-Day

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Brilliant new multi-material desks from Because We Can

With wood, resin, CNC tools and Talent, Oakland’s incredible furniture studio Because We Can turns out another masterpiece.I’ve been a fan of Because We Can for a long time, so much so that I filmed an interview about their work and philosophy. They’re incredibly open about their business model, methods, and techniques. They’ve even given free lectures on how to follow in their footsteps.

Their latest project is a set of interlocked swiveling tables for a San Fransisco home and I have to say I’m astounded. They’re made from wood and aluminum sheets routed on a ShopBot. The real brilliant part comes in how they’ve etched the surface of the table tops using an engraving bit, and then filled the resulting voids with contrasting resin. The finished table is, I think you’ll agree, stunning. More details and video after the jump.

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DIY Hemoglobin

Todd McFarlane Toys and 3D studio Steffen VFX team up to bring microscopic molecules to the macroscopic world.

What do you get when you enlarge a Hemoglobin molecule 725,715,734 times? You get this intricate nebulous sculpture, as the folks at Steffen VFX have demonstrated.

It all started when the team over at Steffen were introduced to David Gittleman of McFarlane Toys. After connecting over comic books they realized they had something more significant in common. Steffen primarily does medical illustration and animation. This usually involves taking scanned data from MRI’s and x-ray crystallography and bringing it into 3d – more or less taking physical objects and turning them into computer models. The folks at McFarlane have made a flourishing business out of making physical versions of fictitious characters. So, that’s when they got thinking about combining their powers. More after the jump. (more…)

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DIY Inkjet Printer

3D Printing innovator Open3DP has struck again with an open platform for 2D Printing.I’ve reported on Open3DP before. They’re legendary for creating innovative 3d printing tech, experimenting in low-cost 3d printing materials, and generally being awesome folks.  Their most recent development continues in their tradition of excellence. Nicholas Lewis of Open3DP developed the open source 2D printer made it available for anyone to download and hack on Thingiverse. Check out a video of the device in action after the jump. (more…)

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3D Printed flat pack dragonfly

Thingiverse user Neophyte shows off the advantages of multi-part 3d printing.I’m a big advocate of using manufacturing procedures to their best advantage. Each procedure, be it FDM printing, sintered steel, laser cutting acrylic, comes with its own virtues and vices. FDM doesn’t allow for watertight parts or hefty overhangs, sintered steel has visible manufacturing artifacts on its surface, and laser cut acrylic contains invisible stress lines from the heat of cutting, making it prone to shattering. However, the advantages of each process are obvious, not the least being the WYSIWYG nature of digital manufacture.

That’s why I’m so happy with this Flat Pack Dragonfly model up on Thingiverse.  The key to its delicate structure is that all its parts are printed flat then assembled, using the stringy structure of FDM models to its advantage.

So, Ponoko people, don’t forget you can print and assemble as easily as printing whole structures.

via: Makerbot Blog

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