Solidoodle:I did it I succumbed to my desire and purchased a 3D printer. Specifically I purchased a Solidoodle 2. A low cost newly released 3D printer. It features a 1.75 mm spooling ABS plastic extruder. 6"x6"x6" print volume, and down to .1 mm vertical resolution. I think it should do everything I want.
The wait time on solidoodle was 6-8 weeks when I order in July and it was quickly extended to 8-10 weeks after I purchased. I hope to see mine sometime this fall and until then I will just have to put up my dreams of things to print. For information on Solidoodle check out their website: http://www.solidoodle.com For general info on 3D printing I suggest: http://en.wikipedia.org/wiki/3D_printing |
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Hagen Arm:This design for this arm was inspired by the arm for the ATAC robot I worked on at Square One, you can check out more about it about it here: http://www.sqr-1.com or on my Square One tab: /square-one.html
The geometric principle at work here is superposition of two circles. The longer "arm" segment defines a circle of a large radius, the short arm defines a circle of smaller radius the length of extension of "head" past connection point defines a proportionality constant between the two circles. The path traced by the "head" is then the geometric average of the two circles. This design allows for a relatively simple one DOF actuator to achieve a complex path. I intend for this to be the first mechanism printed on my Solidoodle when it arrives. |
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Soildoodle Arrives!
Solidoodle finally came in the mail here are some preliminary pictures:
I started with printing a bottle opener from thingiverse and it came out really well! I plan to do a few more prints on some sample items before starting in on some of my own prints. Results will be posted!
Initial Printing: The Good & Bad
Today marks 3 weeks using the Solidoodle 2 Pro for printing I am going to start with some statistics:
1. Intermittent Extrusion
Symptoms:
Results:
With a cleaned extruder and higher temperatures this problem seems to be resolved. Any problems are now only observed when printing rafts. Rafts require the highest flow rate through the extruder so it make sense that they would show symptoms first.
2. Parts Breaking Off Build Platform During Print (Part Slip)
Symptoms:
Fixes Tried:
Results:
All of the fixes seemed to help the problem. I think that certain print files are simply more prone to breaking off than others. The file I had lots of trouble with is the Heart Gear (http://www.thingiverse.com/thing:32037) this print involves a lot of small tall pieces with non-connected rafts. Each of the parts also get significantly wider as they go up which results in an increased moment arm between the part and the base. I think the combination of the particular raft solution and geometry of the pieces results in a print that is very difficult to get to stick. In general I would say most prints will never have a problem.
- 85% Success rate over 50 prints (with raft)
- 60% Success rate over 10 prints (without raft)
- Out of the box 18 prints @ 10 machine hours without failing, after that some spotty performance.
- Prints worked at .2, .25, and .3 (mm) layer thickness
- Longest print 4:35:12 hrs
- Average response time for support@solidoodle.com 1 business day over 5 contacts
1. Intermittent Extrusion
Symptoms:
- On rafts the thickness of a raft strip will vary from 2mm to .1mm.
- If a print finishes a layer may have been missed which creates a structural fault that causes failure at that layer.
- When manually commanding extrude moves a manual extrusion command over 9 mm will cause extruder drive gear to slip on filament.
- All of these behaviors are intermittent and will appear and then vanish.
- Before every 4 prints I like to undo the thumb screw on the extruder tension arm and access the maintenance port to clean out shavings. A pipe cleaner or canned air work great for this.
- When the extruder was barely working I tried this fix: I heated it too 205 degrees C with no filament in it and pushed an acoustic guitar string through the back-end. The string an D string, not sure about the diameter, but the wrapped wire pattern caught the partially melted plastic withing the PEEK tube and allowed me to pull out a lot of material.
- When the extruder was clogged (no flow) I used an electric guitar string, High E @ .085 gauge, and filed the tip down until it would fix into the brass extruder nozzle. Then with the extruder heated to 205 degrees I inserted it about 3/8" into nozzle and broke up the clog.
- I crank down on the thumb screw on the tension arm pretty hard. Everything seems to work best with the spring compressed near to maximum compression.
- The default Skeinforge profile for Solidoodle puts the extruder temp at 190 degrees, I have been printing with better luck anywhere from 195-200 degrees.
Results:
With a cleaned extruder and higher temperatures this problem seems to be resolved. Any problems are now only observed when printing rafts. Rafts require the highest flow rate through the extruder so it make sense that they would show symptoms first.
2. Parts Breaking Off Build Platform During Print (Part Slip)
Symptoms:
- At some point during a print the model will be knocked off of the build platform and the print will fail due to the resulting misalignment.
Fixes Tried:
- Fixed extruder problems so that rafts print more evenly and consistently
- Adjusted initial print height screw. This screw can be found on the back side of the Solidoodle chassis; it contacts the limit switch on the z-axis stage. By raising and lowering this screw you affect how the first layer/ raft is laid down. Rafts should be pushed flat by the extruder head, I seem to have best results when a raft strip is twice as wide as it is thick. I usually just tweak it until the raft looks right. The window of precision is only about half a turn of the screw wide so it takes some time.
- Checked build platform level. If your build platfrom is not perfectly level the raft/ first layer will not bond evenly to the build platform. Adjusting the build platform should only be taken if you are very certain you know how to fix it. Do not guess and check.
- Increased build platform default temperature to 90 degrees. This seemed to help bottom warping as well as make the raft stick better.
- Cleaned build platform with detergent.
- Sprayed thin layer of hairspray on platform before printing.
- Manually edited Gcode for print files so that rafts had greater surface area.
Results:
All of the fixes seemed to help the problem. I think that certain print files are simply more prone to breaking off than others. The file I had lots of trouble with is the Heart Gear (http://www.thingiverse.com/thing:32037) this print involves a lot of small tall pieces with non-connected rafts. Each of the parts also get significantly wider as they go up which results in an increased moment arm between the part and the base. I think the combination of the particular raft solution and geometry of the pieces results in a print that is very difficult to get to stick. In general I would say most prints will never have a problem.