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Preparations

Attention: Running the reprap with wrong parameters may inflict serious damage to the extruder or the base plate!

To get reliable prints you have to find out the correct parameters for your extruder and material. This includes the distance from the base plate, temperature and speed.

When running the extruder at a too low temperature may result in pressure building up inside the extruder. This can damage the ptfe tube beyond repair. You have to recalibrate the temperature settings for every new material you are using. Even the same type of material on different rolls may have different parameters.

To get some initial values to work with follow the instructions which can be found at the blog from bits from bytes.

See http://rapmanv3.blogspot.com/2009/05/extruder.html and http://rapmanv3.blogspot.com/2009/05/printing.html

A short summary: Adjust the bed according to the instructions. When laying out the bed the nozzle should press the extruded plastic a bit onto the bed so it sticks good.

Using a sheet of paper is a good method to test the distance of the extruder head to the table. The head should move freely above the paper. If the head is too close the the table, the head can clog which results eventually in disaster. (ABS melting into the table, ptfe-tube expands and rips)

If you hear a clicking noise from the feeder assembly, don't just blindly tighten the screws, maybe something is wrong, either the temperature is too low, or the feeding speed is to high or the head is too close to the table.

To get a initial temperature to run with heat the extruder to the desired value. Then try to feed the plastic by hand. If you can produce some nice filament by hand fasten the clamps pressing the plastic to the shaft. We had some success using ABS at 240°C.

If you set a temperature that is too low you might damage the extruder by building up to much pressure. If you set a to high temperature the ptfe may fail.

Check if you can restart the machine reliably from a cold state.

Now you can try your first print which will be a “schnaps glas” ;)

The raft for the minimug is very strong. The first layer is printed out at 1/4 the normal speed producing a very thick filament. The next layers are printed at a faster speed.

Skeinforge

Schneider uploaded a skeinforge version including a .skeinforge directory with the parameters from the bfb blog and some of our temperatures.

It uses a setting of 246°C, 40rpm and 16mm/s. The temperature is higher as required as the software of the repman keeps the temperature ca. 5°C bellow.

Use this package at your own risk!

Repdist from Schneider

Printing

WARNING: It is absolutely necessary to restart the Repman after completing/aborting a print or else the repman might damage it self. Do this also when exiting the file chooser menu

For example the head might move into the base plate producing a hole :(

Select the Print Object menu item and use the right up/down-Keys to choose a model to print.

There is some filament extruded while heating up. Remove this with some tweezers to before the head starts moving when it reaches the target temperature. This might be necessary again between layers.

Printed objects and configurations

Date Name Object Description Modeler/CAD weight Link to Thingiverse Configuration changes Pictures Comments Copies
11.06.2009 shot_export.bfb Bigger shot glass Blender n/a n/a Standard n/a Quite a good print. Only weak layer 1
11.06.2009 empire_state.bfb Empire Statebuilding n/a 10g http://www.thingiverse.com/thing:625 none todo good print 1
12.06.2009 key_export.bfb Handcuff Key / Vertical Blender ~3g n/a Standard n/a Extruder much too fast ⇒ not enough time for layer to get hard 1
12.06.2009 key_export.bfb Handcuff Key / Vertical Blender ~3g n/a Extruder speed: 8mm/s n/a slower extrusion, but forgot to set PWM feed accordingly ⇒ extruder tried to feed too much 1
12.06.2009 key_export.bfb Handcuff Key / Vertical Blender ~3g n/a Extruder speed: 8mm/s, Flowrate PWM: 180 n/a Quite good print. Only “beard” of key is not very hard 1
12.06.2009 meter_key_export.bfb Utility Meter Key n/a n/a http://www.thingiverse.com/thing:88 Standard http://www.thingiverse.com/thing:198 Good print 3
12.06.2009 Untitled_export.bfb Servoholder AOI 15g n/a none n/a 50mm x 60mm wraping is visible 1
13.06.2009 http://www.thingiverse.com/download:1429 Box lid n/a 10g http://www.thingiverse.com/thing:635 none n/a n/a 1
15.06.2009 kleinbottle from bfb-forum Kleinbottle n/a 14g - 9r n/a - 1
17.06.2009 pyramide with eye Illuminatenpyramide n/a 11g n/a 9r n/a - 1
17.06.2009 meter_key_export.bfb Utility Meter Key n/a 4g http://www.thingiverse.com/thing:88 9r n/a - 1
20.06.2009 ScrBoxT.bfb, ScrBoxB.bfb Screwable Jewellery Box MetaCAD 20g http://www.thingiverse.com/thing:413 codec n/a Bottom sucks, 2nd top print is great. Screwing works anyway. 2

Calibration

The aim of this calibration process is to find skeinforge parameters for a better print quality and to better understand the influence of those parameters.

With this first test series I'm trying to get watertight floors.

For this purpose I am using a very small mug shape I created in aoi, so printing does not take too long.

run parameter observations
1 schneiders refenzconfig floors are not tight enough; ok from side view; sometimes layers do not connect properly
2 “Extrusion Width over Thickness” erhöht von 1.5 auf 1.8 not much better
3 lowered “Feedrate” to 12.0 mm/s too low, ⇒ klicking ⇒ abort
4 “Feedrate” to 14mm/s no visible difference in the floor layers compared to “2:”

just realized something: in the doku of skeinforge-speed “extrusion fill density ratio”

"fillament diameter"/"extrusion width"/"layer thickness" should be ~0.82; right now its somewhere at 68

run parameter observations
5 Reset “Feedrate” to 16mm/s and “Extrusion Diameter over Thickness” 1.38 not much better
6 reduced feedrate to 8mm/s and Flowrate PWM to 250 much better, but a bit clicking in the first base layer
7 raised feedrate back to 16mm/s and Flowrate PWM to 480 and “Base Layer Thickness over Layer Thickness” to 0.5 further improvment, no clicking, raft: very thin first layer
8 raised FLowrate PWM to 520, raised “Base Layer Thickness over Layer Thickness” to 0.7 very thin in the first raft layer and clicking ⇒ aborted
9 feedrate 10, Flowrate PWM 300, “Extrusion Diameter over Thickness” 1.5 minimal improovement
10 “Base Infill Density” from 0.5 to 0.3, increased “Flowrate PWM” to 480 while printing best quality so far
11 “Base Infill Density”from 0.3 to 0.35 “Flowrate PWM” = 470 teh horrors!!1! WORST QUALITY SO FAR
12 “Base Infill Density”from 0.3 to 0.35;“Flowrate PWM” = 470;
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  • Last modified: 2021/04/18 12:33
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