Fred's RepRap and FabScan Website
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|Who the heck is Fred?
of all tools used in the construction of the RepRap.
rods and waiting for parts to arrive.
|Wrong smooth rods, problems with bar clamps and about open source projects.|
|Mounting the linear bearings and constructing the extruder.|
|First test runs: problems with optical endstops.|
|Calibration, first test printing, problems with the heated bed.|
|More problems with
the heated bed and the heating of the extruder.
|Some considerations about endstops|
Constructing a prototype for a new endstop
Intermezzo: Assembling a custombuild desktop computer
RepRap Heating Issue
RepRap Heating Issue continued
Blog ends per end of June 2014, one year after the project started. At
that time the RepRap finally worked as expected and could manufacture
routinely the objects of my choice.
The Blog may be continued in future with the construction of a FabScan 3D scanner, but financing the scanner project competes with another project currently running, which can be found at www.fusor.eu
What is a RepRap?
A RepRap is a type of 3D-printer, capable of making most of its own parts. It is a machine that fabricates objects by means of fusing a thin filament of a heated thermopolymer material, e.g. PLA (polylactic acid), ABS (acrylonitrile butadien styrene), Nylon (polyamide) or HDPE (high density polyethylene). Each material has its own specific properties, making it suitable for manufacturing objects with specific characteristics (flexibilty, hardness, size-holding, water resistance, etc.). The thermopolymer is mechanically fed into the machine as a 3 mm or 1.75 mm diameter filament and enters a heated extruder where the thermopolymer melts. The melted thermopolymer exits the extruder through a nozzle opening in the printing head with a size diameter ranging from 0.2 to 0.5 mm. The size of the nozzle opening determines the diameter size of the melted filament that is positioned layer by layer on a heated printing bed, thus building the object by means of fusing the filament into layers. The smaller the nozzle opening of the print head the more detailed the object will be but on the other hand the more time it will take to manufacture it. Usually the chosen size of the extruder nozzle opening is a compromise between speed of manufacture and detail of machining.
Rationale for the project.
In June 2013, in our summer residence in France, I was waiting for a (professional) job to start. As usual lots of hard labour were to be done on the estate, but that is just working with your mind set on zero. Lacking a sort of an intellectual challenge I decided to start with the construction of a 3D printer, a RepRap Mendel Prusa i2.
The name is a mouth full but it simply describes a 3D printer which is basically a self-replicating rapid prototyper (RepRap) of the second generation (Mendel, first generation was Darwin), improved by Joseph Prusa (Prusa), second iteration (i2). See for more information: RepRap Wiki and wikipedia reprap.
Image 1 shows a Darwin of the first generation and image 2 shows a Mendel, the second generation at a more advanced level of improvement than the RepRap I intend to build. These improvements are amongst others the stepper motor for the X-axis (middle of the photo, far left side) which has been mounted to operate in a horizontal plane compared to my standard Mendel i2, where this stepper motor operates in a vertical plane (see my RepRap photos on the September 2013 page). Furthermore, the two stepper motors for driving the Z-axis have been mounted at the bottom of the frame, thus lowering the center of gravity.
A further improved Mendel, the i3, is shown in image 3. This version is in my opinion better looking and provides more easy access to the printing surface but was not considered for my project because it requires (large size) laser cutted parts, which were too costly to ship to our summer location.
A further development is the MendelMax2, shown in image 4. The MendelMax has been improved by constructing the frame from aluminium extruded profiles and by using linear rail for the X- and Y-axes as well as precision shafting and bushing for the Z-axis consisting of trapezoidal threads as clearly can be seen in the photo as well as the helicoil couplings that connect the threads with the stepper motors. In this design I dislike the placement of the two Z-axis stepper motors in their elevated position. Preferably they should have been placed at the bottom of the machine for a lower gravity center.
Construction of the MendelMax may require a better equipped workshop with a lathe and a shaper (milling machine). Advantages of this RepRap are the larger print area dimensions of 230x310x225 mm and a resolution for the X- and Y-axis of < 0.0125 mm.
Finally, image 5 shows all the printed parts for a Mendel i2, including parts for the extruder.
Image 1: The first generation: Darwin (image: http://reprap.org)
Image 2: The second generation: Mendel i2 (image: http://reprap.org)
Image 3: The second generation: Mendel i3 (image: http://reprap.org)
Image 4: MendelMax2 (image: http://reprap.org)
Image 5: Collection of printed parts for Mendel i2 (source: RepRap World: RepRap World)
Investments required for the project.
For project control I have carefully kept track of all costs and sourced all items through eBay from all over Europe for realising the cheapest prices. The table below lists all items procured:
Table 1: Project costs
The RepRap can be built for less than 400 EUR, which is about twice the amount that I had initially set as a preliminary objective (see below). A complete kit from a commercial source will cost about double the amount that I had invested. A ready for use machine will start at prices from 1000 EUR and more. It is however expected that demand for home-operated 3-D printers will rise and therefore prices shall decline.
Objectives for the project.
My objectives to construct the RepRap were the following:
The objective not spending more than 200 EUR appeared impossible to meet. Items 2 and 3 of the objections clearly are contradictory and as usual I could not resist to 'improve' the design by integrating better suitable components like helicoil couplings (to kill in the Z-axis inaccuracy caused by wobble), belt gears made of metal (to prevent both in X-axis and Y-axis inaccuracy from slack), compression springs in both Z-axis idlers (to kill in the Z-axis inaccuracy caused by slack in the M8x1.25 mm threaded driving rods), etc.
Additionally, lousy quality of some electronic components forced me to invest in buying extra mechanical endstops to replace defective optical ones and an entirely new RAMPS electronic circuit board (the first one had a component burnt out). Moreover, a few investments needed to be made in some extra tools, which were not present in our summer residence, but that is just considered as a luxury problem!
The additional costs have not been accounted for in table 1, because the purpose of the table is to demonstrate the minimum investment to be made for constructing a RepRap. Bad luck and wrong choices inevitably cost extra!
Philosophy of the project.
As with most of my projects the general philosophy is that the journey is more important than the arrival. This means that I am never hurrying to reach the finish. Daily life brings different duties to fulfill, either for my profession or for maintenance of the estate, next to the usual social events and activities. Inevitably this caused that working on the RepRap project only was done a few hours per day, a few days per week. No problem, because I had ordered the components by mail from all over the world and therefore sometimes had to wait for weeks before a required part arrived. Ordering by mail was the only way to obtain components apart from M8 threaded rods and M8, M4 and M3 nuts, washers and bolts which came from a local construction materials shop. Living in the middle of nowhere (or as it is called in France: "au milieu de nulle part") has its advantages but also its restrictions. Rather outrageous was one day a small note that I found in our mailbox telling me that the postman could not deliver my ordered 2 meter long smooth rods because they did not fit in his car. I was kindly invited to collect them myself in a nearby distribution centre!
Considering the simple design of the RepRap and the easy to find hardware for this contraption and despite my general philosophy I expected to fabricate my first ABS 'things' within a few weeks. However, a year later I found myself still busy resolving problems!
Would I do it again? Yes, because it is an experience that gives a lot of satisfaction by learning different techniques and by resolving problems.
Would I make a RepRap Mendel again? Probably no, because developments in RepRap world do not stop and more exciting types can be built now, e.g. a RepRap Rostock which is a delta type of 3D-printer.
This website/blog will inform you about the (typical) difficulties that I have encountered. Progress and non-progress have been listed per month.
|Enjoy my RepRap world and follow me on my journey through the project! Move to the table of contents and click the first page: June 2013 or have first a look at the tools that have been used.|
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Animations on this website by Dave Sutton: Sevenoaks Art
All images without references on this website (in particular the 'builder' image in the header of all pages): courtesy of http://reprap.org