RepRap Masterclass
Submitted by ronn23 on Wed, 09/16/2009 - 10:58
The RepRap is a do-it-yourself 3D printer, capable of reproducing (most) of it's own parts. The name RepRap is deducted from Replicating Rapid Prototyper, designed by Adrian Bowyer, professor at Bath University, England. Instructions and all necessary data are available completely free of charge to anyone who wants to build a personal 3D printer.
The masterclass started the 15th of September 2009, and will continue for three months. We will be building a new version derived from the RepRap 1.0 Darwin. I will provide a weekly update of the progress.
Darwin consists of a frame made from rods and printed parts. A flat
build platform moves vertically in that frame, driven on screw threads
by a stepper motor. At the top of the frame there are two write heads
that move horizontally (driven by toothed belts and two more steppers)
extruding a thin stream of molten plastic to form new layers on the
build base. The machine prints layer by layer to form a solid object.
The build base then moves one increment down, the second layer is
extruded, and so on. There are two heads to allow a filler material to
be laid down as well as the plastic. This filler is used to support
overhanging parts of the objects being built, and is removed when the
process is finished.
The RepRap 1.0 Darwin has the following characteristics:
- Working volume: adjustable, but nominally 230mm (X) x 230mm (Y) x 100mm (Z)
- Working materials: Polycaprolacone and a filler/support
- Configuration: 3-axis Cartesian drive using stepper motors
- Line and space: 0.5mm and about 0.2mm
- Feature size: about 2mm
- Positioning accuracy: 0.1 mm
- Layer thickness: adjustable, but nominally 0.3mm
- Computer interface: USB
- Material handling: Two fixed material deposition extruders, user exchangeable
- Power supply needed: 6A max, 3A continuous at 12V DC
- Driving computer and operating system needed: Microsoft Windows, Linux, Unix, or Mac
- Exterior dimensions: adjustable, but nominally 600 mm wide x 520 mm deep x 650 mm high
- Weight: about 14 Kg
source: reprap.org
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Project Blog
RepRap Masterclass | Part Eleven
RepRap Masterclass | Fabmoment #11
19th of February, 2010
reprap collective 2010
reprap darwin | next generation
final preparations news broadcast NOS
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RepRap Masterclass | Part Ten
RepRap Masterclass | Fabmoment #10
19th of January, 2010
reprap collection 2010 electronics
extruder complete assembling the axes
silver welding we're getting close
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RepRap Masterclass | Part Nine
RepRap Masterclass | Fabmoment #9
30th of December, 2009
group 1: electronics
etching the print boards testing the circuits
designing the print boards assembling the circuits
group 2: frame building
preparing the assembly blocks assembling the horizontal frame
assembling the vertical frame using custom rulers
group 3: extruders
redesigning the loose axes drilling the extruder heads on a lathe
instructions for silver welding drilling the isolator 'peek'
silver welded thermo-wire assembling the extruder head
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RepRap Masterclass | Part Eight
RepRap Masterclass | Fabmoment #8
10th of November, 2009
this week we divided the group into three sub-groups, so that we can work more efficiently with everyone having a specific task. one group will work on the electronics (rob/ron), another group on the extruders (elmar/arjan), and the third group will work out the frame (sam/steven/tom/jaap). the casting process is near completion, which will be an extra responsibility for the frame group.
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RepRap Masterclass | Part Seven
RepRap Masterclass | Fabmoment #7
3rd of November, 2009
this week for the first time we all had the feeling that we’re getting somewhere. we’re getting close to finishing the casting process and after only having horizontal axis so far, we’re also started assembling on the vertical plane. the laser cutter was used to continue manufacturing the extruders and imperfect parts were finished properly. finally we’ve gotten quite far with preparing the electronic circuits.
• filing out imperfect holes of cast parts
o equipment: sanding file
o the most efficient way to do this seems to be manual labor
o apply the trial and error method to finish up
• laser cutting and assembly of the extruder parts
o material: acrylic
o laser settings: speed [3], power [100]
• vertical assembly process
o make sure that the connecting blocks are at the appropriate position
o relative distances to be used can be found at reprap.org
• electronic circuit assembly
o carefully solder the pre-ordered parts on the print board
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RepRap Masterclass | Part Five/Six
RepRap Masterclass | Fabmoment #5/6
27th of October, 2009
for the past two weeks we’ve continued casting the connecting parts of the reprap, as well as laser cutting the parts for the extruder. the cast parts that came out slightly screwed were adapted to be functional and we’ve started assembling the electronic circuits. finally, the first complete extruding axis was created.
• drilling out imperfect holes of cast parts
o machine: drill
o make sure the parts are fastened carefully before drilling
• laser cutting and assembly of the extruder parts
o material: acrylic
o laser settings: speed [3], power [100]
• assembly of the extruder axis
o first complete assembly
• electronic circuit assembly
o carefully solder the preordered parts on the print board
• finishing the silicone casting mold
o carefully open the silicone mold by slicing it horizontally about half way through
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RepRap Masterclass | Part Four
RepRap Masterclass | Fabmoment #4
13th of October, 2009
this week we’ve continued the process of poly-urethane casting. we’re getting close to completing this part of the manufacturing process. to speed up the process we’re creating a new silicone mold for a part that we need in quite a big number. others started with the assembly of the carrying axes. finally, time was spent on drilling out imperfect holes of some casted parts.
• drilling out imperfect holes of casted parts
o machine: dremel with a sanding head
o low speed, precise adjustments (press fit)
• assembly of the carrying axes
o carefully fasten the parts and try out the strength on each other’s head
• creating a silicone casting mold
o first print the negative parts for the mold using a commercial 3D printer
o carefully clean the printed parts
o sand the printed parts until their surface feels really smooth
o create an airtight mold casing
o to be continued..
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RepRap Masterclass | Part Three
RepRap Masterclass | Fabmoment #3
29th of September, 2009
this week we’ve focused our attention on ‘more of the same’, but also on new developments.
on one hand we continued with casting the poly-urethane parts and laser cutting the necessary gears.
on the other hand we started drilling out the holes in the poly-urethane parts that were accidentally covered during the casting process, and we began carving screw thread from the metal rods.
• continuing the process of poly-urethane casting
o about seventy-five percent of the total volume has now been realized
o the process speeds up once a ‘casting rhythm’ has been developed
o there were still some imperfect parts coming out of some two-sided molds, this was due to the temperature of the
molds. when they’re overheated, the viscosity of the casting fluid decreases significantly when it’s poured in,
thereby cluttering the air release vents.
• laser cutting the gears
o material: 6mm acryl panels
o laser settings: speed 3, power 100
o for part size, take into account that the laser melts away about 0.1mm from the part diameter
o produce one, test it, then produce more
• drilling through the partly covered holes of some cast parts
o carefully fasten the parts on a flat surface to make sure the holes are cut straight
• carving screw thread
o first drill through the holes with a 4mm drill (M4)
o then carve the screw thread with a 5mm carving tool (M5)
o beware that the carving tool is positioned in such a way that it’s prolonging the direction of the hole at all times
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RepRap Masterclass | Part Two
RepRap Masterclass | Fabmoment #2
22th of September, 2009
this week we’ve applied the same methods I’ve described before. since there are many parts that need to be cast for holding the entire structure together this has the highest priority. two or three people suffice for this process. some others concentrated on creating extra silicone molds to increase the potential production speed. the rest of our team focused on documenting the parts created so far and measuring the lengths of the axes to create the xyz-frame, which we’re going to connect using the poly-urethane parts.
• continuing the process of poly-urethane casting
o this time we used wooden planks to supply the two-sided molds with more pressure than before.
o drill holes in the wood to create room for the paper cones
• sizing up the metal axes
o measure all the axes featured in the reprap (or look them up in the online documentation)
o use a metal saw to cut the axes to the desired length
• documenting the parts that were cast
o we took hi-res pictures of the parts we’ve created so far
o this way it’s easy to keep track of the amounts needed and the amounts that we’ve realized to this point
http://www.movingconcepts.org/reprap/
• creating extra molds
o we’ve created new silicone molds for the parts that need to be cast in great numbers
o we've sanded the printed parts carefully to achieve smoother mold surfaces
• start building the x-axe
o by looking at the example reprap we could figure out what parts were needed to put together the x-axe
o the main components are the metal axes themselves, some poly-urethane parts and a few gears that were created
using the laser cutter (material: plexiglas)
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RepRap Masterclass | Part One
15th of September, 2009
• introduction to the fablab concept
o powerpoint presentation
• introduction to the reprap darwin 1.0
o prototype review
• introduction to protospace
o guided tour
• step one | urethane casting of the structural joints and bones
we’re using the casting molds that were created during the previous reprap masterclass. these are available for public use at Protospace Utrecht. if you want to create these negative molds yourself, you’ll have to apply the process I’m about to describe by using printed models of the necessary parts, and replacing the urethane ingredients with a silicone liquid.
o preheat the oven to a steady 150C
♣ this is based on the specific casting material we applied:
♣ part A: water clear casting plastic
♣ part B: rigid urethane casting resin
♣ brand: crystal clear
♣ available at: formX, Amsterdam
o grease the silicone casting molds with Vaseline
♣ try to apply a smooth layer, since the grease won’t melt in the oven and therefore it’ll leave marks on your parts.
o heat up the greased casting molds to 150C
♣ safety first
o meanwhile, start mixing the casting materials
♣ in our case: part A - 100%, part B - 75%
♣ try not to overdo it volume-wise, the parts are relatively small and even at room temperature the urethane will start
to solidify from the moment you start stirring.
♣ when you’re stirring the liquid will first gain some color, but it eventually clears up when it’s mixed properly.
o remove the encapsulated air bubbles by using a vacuum pan
♣ don’t position your head over the machine while it’s in operation, because the cover might implode and the pieces
will bounce back in your face.
♣ the process takes about a minute, if the liquid starts cooking it’s because the boiling temperature of any liquid is
significantly lower in a vacuum environment.
♣ when the bubbles are out, gently release the vacuum and take out the liquid.
o take some heated molds out of the oven and start pouring in the liquid
♣ regarding the double-sided molds you need to make sure that the holes for material input and air output are
extended by cone-folded paper. this way they don’t get cluttered as easily.
♣ make sure the filled molds are placed on an even surface, let them cool down for about 15 minutes.
♣ gently remove the cast parts from the silicone molds. when they’re still slightly flexible you can flatten them some
more by pressing the parts onto a flat surface.
o apply some new grease to the emptied molds and place them back into the oven, repeat the whole process until all
necessary parts are created.
♣ it’s recommended to closely keep track of the necessary numbers and produced numbers to avoid overproduction.
♣ the results of this first day were sizable, about twenty parts created.
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