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Raptosaur at the World 3D Printer Expo in Burbank

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I was invited to show Raptosaur at the World 3D Printer Expo in Burbank with my MakerSpace: Vocademy, as an example of something built there.  This was a very exciting experience.  (I’m not in the photo above, taken at a quiet time).  We were right next to the See Me CNC booth.  We had a lot of interest, often with people 3-deep interested in the printer and Vocademy.  I was very encouraged by comments from the other printer vendors.

In order to get ready for this show, I installed a top surround made from thermoplastic that I bent using my plastic bender.

I replaced the Rumba controller with a Smoothieboard, which is a 32-bit controller.  This was the best thing ever, as the Smoothieboard runs much better and is easier to configure.  Using the Smoothie I was able to finally get the auto-bed-leveling to work, to within 0.02mm which is about 0.0007 inches.  I made a script that automatically extends the z-probe, probes the bed, and retracts the probe.  Having this working was a big relief, as it makes printing large objects possible – the first layer must be printed at a very precise height in order to stick to the bed properly.

I had a piece of 3/16″ mirror glass cut to size for the print surface.  Mirror was used because it is very flat, and it looks good too.

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I also had replaced the heavy black cooling hose with cpap hose and two printed adapters.  This tubing is used to blow cool air from outside the heated chamber to cool part of the hot-end, and also to cool the top of the printed part.  This was much lighter, and allows the printer to move much faster.  Another benefit was that I could remove the keychain keeper cable that I had used to hold up the heavy black hose.  This was putting enough random torque on the effector that it was causing problems.

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We learned by testing at the show that it was extruding at a too low temperature.  This causes the extrusion to be inconsistent (banding), causes printed corners to be pulled around, and causes the filament drive gear to clog with filament chips.  It’s working much better now.  I have to balance the extrusion temperature with the cooling air blowing on the part – small parts can overheat more easily due to the heated chamber.  I believe I can program the fan speed in Slic3r depending on the size of feature it’s printing.

What’s next: I ordered a replacement filament drive gear as the threads on the one I made were not perfect,  and I need to build some fan controllers.  And I have a large commission to print…

There was a lot of cool stuff at the show, I’ll post that separately.

Raptosaur – my new large format 3-D printer

Raptosaur

I’ve been finishing my new 3-D printer.

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A view Inside the enormous print area.

A view Inside the enormous print area.

Here is a link to a video of one of it’s first prints: Raptosaur.

I was printing a leopard seal skull from digimorph.org at 30% scale, at the Mini Makerfaire at Vocademy in Riverside CA.  When it’s calibrated I will be able to print this full scale.  I want to provide full size fossil and animal skulls to local schools.

The features of this printer:

  • Large printing area: 14″ diameter (or as wide as 17″) by 24″ tall
  • Temperature controlled build chamber to allow building big without shrinkage problems
  • Double pane Lexan window
  • Magnetic ball joints for low friction no-lash movement
  • Carbon fiber rods
  • High temperature neodymium magnets in the carbon fiber rods attach them to the ball joints
  • Heated build plate made from cast aluminum tooling plate
  • High resolution (400 step), high torque Nema 23 stepper motors
  • Custom direct-drive Bowden Extruder (using the same model stepper)
  • Custom Hot-End using coaxial cooling (details in another post)
  • The case is built using 3/4″ MDO plywood
  • A Rumba controller (for now)

In the video I had just gotten the printer working, with a few bugs to iron out.  Since then I have:

  • Adjusted the accelerations to fix problems with missing steps.
  • Ground flats on the stepper motor shafts to keep the pulleys from slipping
  • Printed stronger parts for the extruder tension leaver
  • Printed a new effector assembly and bearing brackets for stronger support of the ball bearings
  • Upgraded to the latest Repetier firmware.
  • Switched from Cura to Slic3r.
  • Built new 1/2″ solid steel stepper motor mounts – these are much quieter!  We built these at Vocademy.
  • Built a mini Hall effect sensor for bed probing
  • Built the power supply board for the heated bed
  • Built the new effector assembly with better attachment for the 1/2″ bearings
  • Built a control panel (version 1).
  • Had an interview with a South Korean film crew, regarding entrepreneurs using maker spaces to jump start their businesses.
  • Installed the new power supply, new effector, tested scripts for deploying and retracting the Z-probe.

In Process:

  • I’m testing the bed leveling in Repetier.  This is not going at all well at the moment, as the Repetier firmware 0.92 is hanging…  That’s the last straw for the Rumba and Repetier, I’m going to upgrade immediately.
  • Install lighter hose for the cooling air system (will require printing some adapters)
  • Finish designing a 0.1 micron ULPA air filtration system that will catch the micro-particles that are emitted.

Still to do:

  • Upgrade to a Smoothie Board – a 32-bit controller, and display.  It’s on order, I can’t wait!
  • Calibrations using Smoothieware
  • Upper surround
  • Finish getting ready to show at the 3d Printer Expo at the end of January!

Here are some pics of finished items:

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    The tiny double-sided board is the hall-effect sensor board for the bed-probe (for auto leveling). The blue boards are for the heated bed power supply.

Mini Hall Effect Sensor board

Mini Hall Effect Sensor board

65v Heated Bed Power Supply

65v Heated Bed Power Supply with soft start.

Effector assembly with Z probe

Effector assembly with Z probe.  Sorry about the angle!

Vase

A vase I printed for the Korean documentary film crew.

Vase Top

Top of the Vase

Control Panel

Control Panel

Creating a Thermal Cycling Rig for Testing Copper Via Rivets

I am creating a rig to test the reliability of Copper Via Rivets. IN PROGRESS..

Latest Update: I’ve re-done the temp sensors using cat-6 twisted pair cable and some other components.  When I can I’ll post pictures.

Update:  I’ve been having problems with the temp sensors reading unreliably.  I’ve tried several things to fix this, but really I have been trying to fix it blind, which is a bit of a pain and somewhat discouraging.  What I really needed was an oscilloscope to be able to really see what’s happening.  The one I found was about $355 on Amazon: Rigol DS1052E 50MHz DSO

Product Image

I found another site where I could order it with free shipping for $336. It only took 10 days to receive the scope shipped from Hong Kong to near Los Angeles, from bestofferbuy.com.  Their standard shipping included a USPS tracking number that worked fine.  I’m impressed with it.  The only issue was they sent it with a “China standard” plug… but the socket on the side of the scope takes a standard computer cord… no problem.

The interesting thing about this scope is that it can be switched to a 100 mhz scope by changing it’s model number etc using the USB port – the same hardware was used for both models!  I’ve done it, no problem. This blog tells how.

This project will now continue, since I’ve figured a way out of my dilemma.  I need to re-make the test board, and test a slight improvement in riveting while I’m waiting for the scope to arrive.

Update: I found some interesting information on the causes of thermal cycling induced failures in industry standard plated vias. According to this article the failure is due to weakness in the plated via wall, and that strengthening the via wall can eliminate the failures and can constrain the relatively weak expansion forces of the laminate. We will see if copper rivets will also behave as stronger vias (being many times stronger since they are solid).

Purpose: to determine if copper via rivets will fail due to thermal cycling.  Assembly and programming are complete, and the test board is complete.  Continue reading

Test Rig Display

Double Sided Test Board ready to etch. This board will have 100 riveted vias in series.

Finished Test Board

Alibre Design – a Great Parametric CAD program

I love this program!  After looking at many different CAD packages I decided on Alibre Design over a year ago – the Personal Edition was $100 then, and it’s more now.

It has a very good sketch mode with parametric dimensioning that stays intimately connected to each object, and you can re-dimension at will. It was a bit of a learning curve, but there are a lot of vids that help a lot, and its well worth the time.

Read More…

You Can Get Your Glasses Online and Save Big Bucks

I recently needed to replace my glasses and found there is a massive markup for glasses frames and lenses.   How much do you think?  100%, 200%?  How about 1000%!!

I found you can order good glasses online with your prescription for as little as $16 or less with shipping.  Yes, it takes about two weeks to receive them, fine!  The usual markup on anti-reflective coating is just as bad, it cost me $50 from my optometrist last time, but costs only $5.00 online.   I was shocked!   Read more…

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