If you are familiar with 3D printing, you may know of one of the most frustrating constraints in the process: overhangs. For those new to the tech, Material Extrusion machines like the RepRap and Ultimaker extrude molten plastic into air to produce 3D objects. But molten plastic is subject to gravity, so each bit of plastic needs to be supported by a previously printed layer.

bottom view of soap dish model

Bottom view of soap dish model

There are a lot of solutions for this constraint. Designing an object not to have overhangs is one approach. Most 3D printers also use one or more materials to print supporting scaffolds for overhanging features. But removing the printed scaffold can sometimes be a mess. Take the example show here of a soap dish:

This model will print really well with the large flat surface placed on the build plate, but the four feet shown in red project below that surface. To print this as is, you would need support structure underneath the entire print with just the feet touching the print bed. Support scaffolding can be a mess, but I have a new method that can avoid support material altogether: flip the print over and print on the nice flat surface. With this approach, the trick is holding the model in place upside down while the feet are printed. The molten plastic will bond to the previously printed part, and the feet will become a permanent part of the soap dish.

3D printed fixtures are already a selling point and common practice in the professional additive manufacturing field, but I haven’t seen any examples of this among the DIYers and consumer 3D printer operators. A 3D printer has the ability to make any tool needed, even single use fixtures for a simple soap dish model. It only takes a bit of CAD to produce a working set of fixtures that will be printed and left installed on the print bed. Take a look at the embedded 3D model below and I will describe the process step-by-step.

  1. CAD your model. I use Fusion 360 because it is quite powerful, and free to use until I start making money.
  2. Create separate bodies for the fixtures and features that will be printed separately. Here the fixtures are in green, and the feet in red. They need to be separate bodies (not joined) so they can be exported separately.
  3. I created the fixtures for this soap dish by starting with a sketch that is in plane with the flat top of the soap dish. Then I extruded that sketch with the option “to object” so it would match the dish’s contour. I also included an offset. See that dialog box here:
    Extrude feature dialog box

    Extrude feature dialog box

     


  4. It helps that this model, the fixtures, and the feet are all symmetrical. The slicing software Slic3r will automatically center our parts in the printer, a feature we will rely on in this process.
  5. Create the additional features as separate bodies, see as red in the model above.
  6. Export 3 separate STLs: model, fixtures, additions. You can export STLs with multiple shells like the 2 fixtures or 4 feet with this trick.
  7. Slice and print your main model as normal.
  8. Slice the fixtures STL, but use the Brim setting to ensure really good bed adhesion.
  9. Edit the fixtures Gcode to remove your end.gcode and anything else that might turn off a heated build plate. Our fixtures need to stay stuck to the 3D printer. My first attempt failed because the print bed cooled down and the fixtures popped right off.
  10. Slice the additional features STL.
  11. Edit the additional fixtures Gcode to remove any start.gcode including homing commands.
  12. Add G92 Z0 to the top of this additional features Gcode. G92 will set the printer position to Z0.
  13. These two Gcode files will printed back to back with your intervention in the middle. Pay attention to the time.
  14. Print the fixtures Gcode. When it ends, place your model into the fixture. If it doesn’t have a snug fit, tweak the CAD to find the right geometry to hold your model. It doesn’t need to be clamped in, just secure enough that the nozzle won’t move your model.
  15. Now manually move the nozzle so that the tip is right at the flat “underside” of the model. Also home X and Y in case they shifted.
  16. Print the additional features Gcode.  Keep a finger on the power or reset button. My second attempt to print this failed because I forgot the G92 Z0 and smushed the nozzle into my print.
  17. If all goes according to plan, the printer will add your additional features directly to your existing model.

Check out a timelapse of my third and successful attempt at adding feet to my soap dish.3d print timelapse

This technique could be used to make more permanent fixtures that can be reattached to the printer. You could use this to 3D print customizations onto previously printed or mass produced items. It may require more plastic than support material, but could save the time and effort of removing stuck-on scaffolding. It’s always good to have multiple options to the same result.

If you do 3D print some fixtures, please share the process or results with me! Happy 3D printing!

p.s. I’m running a 3D printed gift exchange this holiday season. If you have the skills and the means, please join up and 3D print a gift for someone else! Join here.

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At the Kensington Kinetic Sculpture Derby and Philly Tech Week (City Hall) This Summer.

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New to the laser cutter? Want a quick intro on the basic workflow of taking a design and cutting/etching it? Want a neat little hive76 keychain? Stop by and see me (pete [the tall one]) during open house!

 

Hive76 will be moving the Open House start time from 7PM to 8PM starting next week (9/21/2016). The reason for the shift is to accommodate member meetings during the 7 o’clock hour, so be on the lookout for more awesome things™ at Hive76!!

See you at the next Open House!

 

As seen in this story published by Technical.ly/Philly

It's alive.....

Hive76/WPPM/PhillyCam Board refurb

written by Dustin Slaughter, Hive76 has teamed up to offer space and expertise to assist PhillyCam and specifically their radio arm, WPPM, get their equipment ready to go on_the_air

 

And there is still time to get involved.

Saturday June 18th from 12 noon to 4pm we’ll be doing it again!

 

All are invited to participate at Hive76 this Saturday.

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Well, I’ll tell you.

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PhillyCam Radio

Sunday June 12th from 12 noon to 4pm we will be opening the space to WPPM.

They will be cleaning and testing their sound consoles to be used at their low power FM station debuting later this summer.

If you want to come down and help, or just watch, PLEASE do so. WPPM is a part of PhillyCam.

PhillyCam, WPPM, and Hive76 all welcome and provide access to anyone with an interest.

There may be more than one session. Stay posted here for further updates.

And later in the month; MORE RF.

 

2016 ARRL Field Day is June 25-26

 

I will be running (with LOTS of help) the G.O.T.A (Get on the Air) station at the PhilMont Mobile Radio Club Field Day event at:

Fort Washington State Park in Fort Washington, PA.

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PhilMont Mobile Radio Club

 

Again, this event is open to all! Lots of RF stuff will be happening. If at all curious, please come out and check out the festivities. Amateur radio. Amateur radio digital modes. Satellite communication. FOOD. SDR radio. Mesh networking and more.

Hope to see you at these events.  …. — .–. . / – — / … . . / -.– — ..- / .- – / – …. . … . / . …- . -. – …

 

 

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Hive Retro Game Night

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Join Hive76 members for one of our signature tech week events, our retro machines and game consoles are dusted off brought from the brink of obsolescence for your enjoyment! Your favorite classic consoles – NES, SNES, Sega Genesis, Game gear, Commodore 64, 3D0, and more – will be available on a ‘does it work and is there a spare CRT tv’ basis, and one of our members will be debuting something new, multiplayer, and completely righteous.

When: Tuesday May 3 7 PM – 11 PM
Where: Hive76 HeadquartersThe Bok Building
Room B06
1901 S 9th St
Philadelphia, PA 19148

 
On Thursday May 5th, Hive76 will be hosting DIY Music Night which will engage participants of all experience levels in electronics, programming, and sound. The event is FREE to attend, participants can pay to take home their instructional materials at cost.
There are two activities to do, design your own analog synthesizer and design your own computer interface. Participants will be able to do both activities if they wish.
Build your own synthesizer
Using breadboards and a handful of very affordable components, participants will get hands on instruction in the field of analog signals. We will be making headphone amplifiers, oscillators, noise generators, filters, and more!Build your own USB control surface
Using a specialized Arduino board called a Teensy participants will get to create USB MIDI control surfaces that will work with any music software. Instructors will be helping everyone to adapt sample code for their unique design. Learn how easy and inexpensive it can be to create your own controller customized to your needs!

7:00 PM
Free to attend, $10 to take home a synthesizer
1901 S 9th St Philadelphia, PA 19148
Entrance is on Dudley st in the middle of the block, look for the touchpad to call a Hive76 member
 

We’re baaaaaaack

It was just over six years ago that we had our last grand re-opening.hive-76-logo

 

I’m pleased to say that Hive76 is about to re-open its door to the public once again, and in our new location! This time around, we thought we’d do things a little differently and decided to kick off our new space with a Grand Open House! If you haven’t been to a Hive76 open house before, why not make your first one a Grand one?!

 

When is this exciting event, you ask? Why, it’s tonight!! That’s right! Make your way to the Bok building at 9th & Mifflin (entrance on Dudley St.) this evening for all of your hackerspace needs! We’ll have plenty of our past projects on hand for you all to play with and our members will be hanging out for any & all of your questions, such as: “How do I become a member of this awesome organization?” We can’t wait to meet you!

 

When: Friday, January 29th, 7-11PM

Where: 1901 S. 9th St., Suite 106, Philadelphia, PA 19148 (entrance on Dudley St.)

How: RSVP here

Why? Because we like you

 

 

 

Announcing Hive76’s–The City Maker

Hello readers!

As some of you know Hive76 has moved into the Bok School on 9th and Mifflin Street. For over 10 years I have lived and made work in South philly. With our maker space now located in the community, I want to make a small publication championing some of south philly’s awesome Makers and Artists.

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Now I’m looking for people making cool stuff! So if you know any, or are one, pass on your information and I will try and include you!

Send your info to me at ChrisTerrell@Hive76.org

 
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