Upon searching, on google of course, for cellular scaffolding I stumbled upon the Wiki article for tissue engineering and additive manufacturing which took me down a rabbit hole. I soon found out about Dr. Anthony Atala, M.D who has already started 3d-printing kidneys. What? This happened 3 years ago. I feel so out of date. Anyway, they are printing cells in some kind of pink gel using a gel extruder which looks to be pneumatically controlled. This is how our first paste extruder is going to operate. We have already ordered most of the parts, it's just a matter of finishing the plan and making the time!
Bioresorbable polycaprolactone has been shown to work great as a medical stint.1 The Scientist has a great mini review of 3d-printing entitled, "Organs on demand"
Monday, September 1, 2014
Tuesday, July 29, 2014
Open-Source Stereolithography (SLA)
Stumbling around later-than-should-be-up on the internet, I found this slideshow presentation. Looking past a lot of grammatical errors, there appears to be very valuable information for 3d printing makers in the open source movement, specifically for FDM (fused deposition modeling) and (SLA) Stereolithography apparatus 3D printer specifications:
I have noted a few companies that sell consumer-level SLA 3d printer.
3DS offers full-color powder-fusing inkjet machines that fuse nylon powder together and color it for you in one step using a printhead.
I have noted a few companies that sell consumer-level SLA 3d printer.
SLA 3D Printers:
Formlabs Form1:
Formlabs has created the Form1, this is the first SLA 3d printer I saw in person when I visited Autodesk's campus @ Pier 9 in San Francisco. I was given a personal tour by my girlfriend's friend. You gotta love making connections with new people. The print is created upside down on a tray.d9-asdf
The print is created upside down again on a plate coated with polydimethylsiloxane (PDMS) which undergoes a sequential dipping and curing process using a z-axis screw and modified high-definition video projector. (the modification is likely the bulbs3D Systems: Projet 1200 SLA
3D Systems (3DS) has been in the additive manufacturing business for quite a long time compared to most other 3d-printing companies. Most 3DS machines are workhorses with large build volumes, meant for industrial prototyping. 3DS offers SLA printers which cure acryllic monomeric resin to make a variety of hardnesses, anywhere from flimsy rubber (Shore 40ish) to hard plastic (Shore 95+). These printers use a nozzle to deposit support and resin mixtures simulateneously, typically these prints are not colored. This model features 585 dpi and 30 micron layer resolution. At $4,900 it is considerably cheaper than any 3DS printer I have asked about. Unfortunately, it uses a proprietary plastic.3DS offers full-color powder-fusing inkjet machines that fuse nylon powder together and color it for you in one step using a printhead.
Friday, July 11, 2014
Our First 3D Printer - A Lasercut RepRap Mendel (Techzone Remix edition)
By us, I mean James Mitchell, Kevin Takalo and I. Currently, we've decided our company name is going to be Hedron. Here are pictures I've compiled of our first 3d printer. This printer came as an incomplete kit, with decrepit generation 3 electronics which we swapped out for Generation 6 electronics pictured below. We then upgraded to RAMBO v1.2 electronics to support a heated bed and made numerous other modifications and upgrades to it. We still continue to make improvements because it is still working well! I will continue to post updates on what we are making. There is still a lot I have yet to document. Enjoy these pictures, they are displayed chronologically starting from the top.
Time lapse video of the printer working is made with 'VideoVelocity
Free' software and a Mcnally IceCam 2 Webcam. they are meant to fit together to form one big tetrahedron (out of PVC).
This is some of my first time-lapse video footage.
Second print of the left eye-piece used a raft for better adhesion, a raft is a few layer solid cushion used to increase surface area and flatness for the part (10mm raft outer margin), but this still detached due to warpage.
Third Test print was also a failure due to lifting. (10mm raft margin).
I applied an ABS-Acetone slurry, composed of 1:1 acetone:ABS scraps thoroughly mixed and dissolved, on top of the Kapton tape with a small paint brush for The Fourth Test print (30 line brim width) and this time the print successfully stayed stuck to the bed. In fact, the print stuck so well to the slurried kapton that I had to rip the kapton tape off to get the print off the glass top.
Steampunk Goggles using 52mm Photographic Filters by guyc is licensed under the Creative Commons - Attribution license.
Owl statue by cushwa is licensed under the Creative Commons - Attribution license.
Notes:
We made a heated print platform out of acryllic aluminum, but after printing with it at ~90 degrees Celcius it warped considerably far from flat. Therefore, we took the advice from the Reprappro Tricolour wiki and sandwiched the heated PCB (Printed Circuit Board) between a 1/4" piece of MDF (Medium Density Fiberboard), which is used as an insulator, and a 3/16" piece of aluminum sheeting, which is a heat spreader. I applied thermal paste to the top of the PCB (the side with the traces) and bolted the three sheets together at all 4 corners with some M2.5 cap screws and nuts. Be sure to cut out the aluminum for the silver traces on the PCB to avoid shorting out your electronics and power supply.* The printer has now has gone through numerous upgrades including RAMBO v1.2 electronics, a 2 mm ID (inner Diameter) teflon bowden tube that connects the printed reprappro tricolour cold-end and the purchased all-metal tricolour hotend. So far we have printed: a plastic x-carriage for the hotend, a spool holder, plastic parts for a Reprappro tricolour mendel 3D printer, plastic parts for a Cherry Pi Delta printer, an iphone 5 bike mount, and some custom designed parts i.e. a silicone mold and trinkets.
*MK2 PCB Heated Bed shorting issue resolved. It turned out I was shorting the silver soldered contacts of the PCB with the aluminum heat spreader and causing the RAMBO v1.2 electronics to reset over and over. The Pronterface (printer interface) software data log displayed a code 'brown out reset' indicating a loss of power (in this case due to shorting). I plugged in the multimeter and measured the resistance of the heated bed between the + and - contacts and found 0.3 ohms. This bed should have a resistance of around ~2 ohms between the + and - contacts and around 4 ohms between the - contacts. After cutting out some of the aluminum for the contacts the heated bed is getting up to 90 degrees celcius (a measured value) in about 5-10 minutes. The thermistor is reading about 10 degrees too high. I have not calibrated the thermistor yet.
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This is the printer when we first got it working |
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You can still see the wires are hanging out bare |
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Some of the first test extrusions. The yellow film is Kapton tape (polyimide film) which helps the plastic stick, the green stuff is PLA plastic (polylactic acid), a corn-based plastic that supposedly is biodegradable |
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Some initial problems we had skipping steps. Offsetting of the layers occurs when the stepper motors skip electronic pulses (steps), or when a belt skips, or when there is binding in the railing. We thought this was due to overheating, so we installed 12V cooling fans and aluminum heat sinks on the stepper motor housings. |
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This neon transparent PLA came as a 1kg roll of filament (1.75mm), we hope to be producing our own types of filaments in the near future. |
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We started with a very simple 20 mm x 20 mm x 10 mm cube to get our axes "steps per mm" values set in the firmware. Currently, we are using Marlin firmware. |
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We had insufficient infill, this was a matter of getting the extruder 'steps per mm' value calibrated in the firmware |
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One of the first bed of ABS parts made for the next 3D printer (RepRappro Mendel Tricolour). You can see the MKII PCB (Printed Circuit Board) heated bed we added. |
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We printed an upgraded Reprap Mendel x-carriage, and upgraded the hotend to the Reprappro tricolour Mendel kit (0.5mm) and made a custom mount for it. |
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This is a Reprappro Mendel tricolour-style heated bed platform (pictured here without the borosilicate glass top clipped on) |
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These are the Rambo v1.2 electronics we upgraded to control our printer purchased from Norcal electronics |
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Here we printed out the green and silver spool-holder arm. Filament spool holder for Prusa Mendel by mpluma is licensed under the Creative Commons - Attribution - Share Alike license. The bowden-style white cold-end (the part that feeds the filament) is from a Reprappro Mendel tricolour. |
Tetrahedron
I printed a tetrahedron that my designer friend, Kris Johnson and I designed together. There are wavy ridges in the sidewalls of most of our prints at this stage due to a phenomenon called "z wobble" (60-100mm/s). Initially, we thought it could be due to overextrusion while laying down the perimeters or slop in the gantry. The wavelength of the ridges is approximately 5 or 6 layers and is consistent from print-to-print. It turned out realignment of the x-axis rods, brearing mounts, and motor mount bracket fixed the z wobble.This is some of my first time-lapse video footage.
SteamPunk Goggles
First print of the left eye-piece failed because the bottom detached from the bed, due to warping of the print while printing. This happens if there is insufficient bed heat and/or adhesion. To increase adhesion we print a perimeter which can be seen around this print, called a brim. This print has a 20 line brim width. A setting we use in Cura, which is the software we use to control this printer.Second print of the left eye-piece used a raft for better adhesion, a raft is a few layer solid cushion used to increase surface area and flatness for the part (10mm raft outer margin), but this still detached due to warpage.
Third Test print was also a failure due to lifting. (10mm raft margin).
I applied an ABS-Acetone slurry, composed of 1:1 acetone:ABS scraps thoroughly mixed and dissolved, on top of the Kapton tape with a small paint brush for The Fourth Test print (30 line brim width) and this time the print successfully stayed stuck to the bed. In fact, the print stuck so well to the slurried kapton that I had to rip the kapton tape off to get the print off the glass top.
Steampunk Goggles using 52mm Photographic Filters by guyc is licensed under the Creative Commons - Attribution license.
Owl statue
printed at half scale, like most all of our prints, has some repeating lines and ridges in the sides from a problem termed "z wobble". Z- wobble is when the z-axis screw rods wobble in circular paths causing the x-chassis to wobble.Owl statue by cushwa is licensed under the Creative Commons - Attribution license.
Notes:
We made a heated print platform out of acryllic aluminum, but after printing with it at ~90 degrees Celcius it warped considerably far from flat. Therefore, we took the advice from the Reprappro Tricolour wiki and sandwiched the heated PCB (Printed Circuit Board) between a 1/4" piece of MDF (Medium Density Fiberboard), which is used as an insulator, and a 3/16" piece of aluminum sheeting, which is a heat spreader. I applied thermal paste to the top of the PCB (the side with the traces) and bolted the three sheets together at all 4 corners with some M2.5 cap screws and nuts. Be sure to cut out the aluminum for the silver traces on the PCB to avoid shorting out your electronics and power supply.* The printer has now has gone through numerous upgrades including RAMBO v1.2 electronics, a 2 mm ID (inner Diameter) teflon bowden tube that connects the printed reprappro tricolour cold-end and the purchased all-metal tricolour hotend. So far we have printed: a plastic x-carriage for the hotend, a spool holder, plastic parts for a Reprappro tricolour mendel 3D printer, plastic parts for a Cherry Pi Delta printer, an iphone 5 bike mount, and some custom designed parts i.e. a silicone mold and trinkets.
*MK2 PCB Heated Bed shorting issue resolved. It turned out I was shorting the silver soldered contacts of the PCB with the aluminum heat spreader and causing the RAMBO v1.2 electronics to reset over and over. The Pronterface (printer interface) software data log displayed a code 'brown out reset' indicating a loss of power (in this case due to shorting). I plugged in the multimeter and measured the resistance of the heated bed between the + and - contacts and found 0.3 ohms. This bed should have a resistance of around ~2 ohms between the + and - contacts and around 4 ohms between the - contacts. After cutting out some of the aluminum for the contacts the heated bed is getting up to 90 degrees celcius (a measured value) in about 5-10 minutes. The thermistor is reading about 10 degrees too high. I have not calibrated the thermistor yet.
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