3D Printing
A place where current 3D printer users can document the process of 3D printing.
Introduction Pegasus Touch Laser SLA 3D Printer
The SLA printer currently being used in the display case in Dennis is a Pegasus Touch by FSL3D. The Pegasus Touch prints with a clear Photopolymer resin, and has a build volume of 7”x7”x9” (177x177x228mm).
FSL3D Resources
See below for a number of helpful resources for operating the Pegasus Touch provided by FSL3D:
Pegasus Touch product page and full system specs
FSL3D Wiki space and Pegasus Touch user manual
FSL3D Software and manual downloads
Safety
There are a number of safety hazards involved in the operation of the Pegasus Touch. Please exercise caution and take note of the guidelines below.
Work Area
The printer must be installed on a level surface in order to prevent resin spillage. It should also be kept away from direct sunlight, as this can interfere with the printing process and effect the resin being used. Although the printer does not emit any fumes, a well-ventilated area should be identified for using isopropyl alcohol to finish printed parts.
Photopolymer Resin
The Photopolymer resin is irritating to the eyes, respiratory system and skin. Direct contact with the liquid resin should be minimized, and exposed skin should be washed thoroughly after handling. It is advisable to use impermeable, chemical-resistant gloves when handling the resin, and safety goggles or glasses if possible. Resin containers should remain sealed, and the opening of the Pegasus Touch should be kept to a minimum while there is resin in the build area. In addition, resin should not be allowed to drip into the Pegasus Touch outside of the build area.
Before handling the resin, see:
Laser Safety
The printer should remain CLOSED while operating. The autolock should only be overridden in the case of an emergency, and only with proper eye protection. Opening the printer during a job, without pausing it, can expose you to class 3B laser radiation.
Setup
- Ensure that the machine is properly connected:
- The ethernet port on the machine connects to the nearby freeport on the wall.
- The power adapter plugs into the nearby power outlet on the wall.
- The DC barrel connector plugs into the power port on the machine.
- If turned off, the machine should boot within 90 seconds of being properly connected.
- Ensure that the build head and resin vat are securely fastened and leveled. If the build head and vat are not securely fastened and leveled, refer to the discussion of the procedure in the maintenance section.
- Ensure that the build head has been properly cleared of all resin remaining from previous prints. If resin remains on the build head, refer to the discussion of cleaning the build head in the post-production section.
- Ensure that you have access to isopropyl alcohol (or a similar alcohol), a safe container to use, and chemical-resistant gloves for the finish process
- Fill the vat with resin up to the minimum fill line, or the first step.
Printing
To print from the Pegasus Touch, first download FSL3D's RetinaCreate software and ensure a secure internet connection:
Download RetinaCreate Software Windows Vista – 8.1
Download RetinaCreate Software Mac OS X 10.9 *ALPHA PREVIEW*
NOTE: The OS X version of the software is EXTREMELY minimal. Thus far we have not had success in using it to print on the Pegasus Touch. Therefore is is highly recommended that you use RetinaCreate for Windows. This has not been done successfully yet, and the only prints created with the Pegasus Touch have been test prints that come pre-loaded on the device. If you experiment with the Windows version of the software, please document your experience here. A good guide can be found here.
Resin
If needed, more resin may be added the vat during a print. To do this, make sure that you pause the print using the LCD interface before opening the printer to add more resin. Do not add resin up to the maximum fill line until at least 10cm of printing has been completed, so that it does not overflow.
Post-Production
- When the model has finished, wait at least 10 minutes to allow excess resin to drip into the vat before opening the lid.
- It is recommended that you insert a cutting board or other safe surface on top of the vat before removing the build head. This is to prevent excess resin from dripping into the machine.
- Remove the build platform by unscrewing the fastening bolt, gently sliding it out, and flipping it over once it is out of the printer.
- Scrape any excess resin back into the vat before taking the model to an acceptable finish station.
Note: finished parts may remain on the build platform form up to several days as long as the lid is left shut and the printer is kept out of direct contact with UV sunlight.
Finishing steps
- Scrape or pull the model(s) off of the build platform (ensure that you are using gloves to prevent direct skin exposure to the resin).
- Place the model(s) into a safe container and submerge them in isopropyl alcohol or a similar alcohol for 15 minutes.
- Remove the model(s) from the alcohol and carefully remove the support structure.
- Rub the build platform with IPA, rinse and dry before replacing it.
- If there is still resin in the printer's vat, make SURE that the lid of the Pegasus Touch remains closed after you are done.
Maintenance
A number of maintenance procedures must be periodically performed to ensure that the Pegasus Touch continues to move smoothly.
Build plate leveling
The build plate should be re-leveled if the build plate and the bottom of the vat are not properly aligned, or if the Pegasus Touch is ever physically moved. A video tutorial that outlines this process may be found here:
Motor calibration
The motor may be manually calibrated if necessary. This will reset the starting z-position of future prints, and should be done if the Pegasus Touch is moved or exposed to significant temperature changes. To manually calibrate the motor, navigate the LCD display to the motor calibration screen and lower the build plate using the ‘Motor Down’ button until it nearly touches the vat. Then, finely adjust the build plate level by opening the case and twisting the lead screw manually. The goal is to leave less than 0.5mm of space between the build plate and the vat. Once this is accomplished, press the ‘Set Motor Homing’ button. The motor will then raise the build plate a few centimeters automatically. Verify that the homing has been set accurately by pressing the ‘Test Motor Homing’ button and seeing that the build plate returns to the position hovering slightly above the vat.
Laser calibration
We have yet to perform laser calibration. Please update this page with your experiences if you calibrate the laser.
Introduction MakerBot Replicator
The printer currently being used in the physics lab Dennis 128 is a MakerBot Replicator. The Replicator can print both ABS and PLA filament, and has a build volume of 8.9" L x 5.7" W x 5.9" H. ((255x145x150mm) It also comes equipped with a dual extrusion system to be able to print objects in two colors.
Makerbot Replicator product page and full system specs
Software
A very user-friendly program to use to communicate with the Replicator is MakerBot's own ReplicatorG, which can be found as a free download here: http://replicat.org/download. There are installation instructions included on that website, as additional downloads are required (Python and some drivers).
3D Modeling
All programs mentioned are free.
OpenSCAD
Open source. Programmatic 3d modeling. Very precise, units in millimeters.
Preparing a model in OpenSCAD for printing
- You’ll need:
- render and compile with OpenSCAD with F6
- export to stl,
- open that stl in ReplicatorG
- center the object and put on platform if necessary
generate gcode
- recommended settings: left extruder, 15% infil, .20 layer height, 35 extruder and motor speed
- Wait.
- After the file is generated go to the gcode tab and modify the numbers on the lines M104 should be 230 and M109 should be 128, i.e.:
M104 S230 T1 (set extruder temperature)
M109 S128 T1 (set HBP temperature)
- export file to disk
Blender
Open source. The best open source modeler out there, very powerful, hard to get to be precise for engineering centric designs. After exporting a model to an .stl you'll want to run the model through Netfabb which will check to make sure the model has no holes or connected meshes that share a single edge.
Google SketchUp
Maintained by Google, tutorials available.
Thingiverse
3D models can be uploaded and downloaded online through a free website called Thingiverse.
ReplicatorG
ReplicatorG is the main interface between the 3D model and the printer. Since 3D models are usually .cad, .obj, or .stl files, the printer cannot directly print them. ReplicatorG uses a tool called Skeinforge to take the 3D model as a .stl file, and turn it into gcode. Skeinforge slices the model into layers and determines what paths the extruder needs to take for each layer based on the parameters set in ReplicatorG. The resulting file is a .gcode file, which can be printed directly from the computer if connected via USB. To print without connecting a computer, the .gcode file needs to be converted to a .s3g file and saved to an SD card, as discussed below.
Interface
ReplicatorG will display a 3D interactive preview of the open .stl file. The column on the right offers some options on how to orient the model on the actual build platform. Some of these options include moving, rotating, or scaling the model before it is printed. It has default "snap-to" settings to center the model on the platform, and move it so that its bottom most side (the first layer) is laying just on the surface of the build platform. A model that lies below the build platform will result in an error and will not print correctly, and a model that lies above the platform will print with severe warping, since the first layer of plastic will have nothing on which to adhere.
Converting to gcode, and Print Settings'
Once the model appears in the preview the way it is intended to be printed, it can be converted to gcode by either clicking on the icon at the top of the screen with an arrow and a sheet of paper with a 'g' on it, or clicking on the button on the column to the right labeled "generate gcode." A new window will pop up with settings for how the model is to be printed.
- Slicing Profile: It is best to use Replicator Slicing Defaults, since the machine being used is a Replicator.
- Extruder: Since the Replicator has a dual extrusion system, either the left or the right extruder can be used.
- Raft/Support: Depending on the shape and orientation of the model, a raft and/or supports might be necessary to print. Objects with flat bottoms and no overhangs do not require a raft or supports. A raft should be used for objects with a rounded, curved, or otherwise nonuniform bottom, or for an object with relatively little surface area on the bottom. The raft will add a stable, flat bed of plastic on which the printed object can adhere. If the object has overhangs, or very steep vertical curves, supports will be needed in addition to the raft. Supports are essentially pillars of plastic printed under the overhangs or curves so that the overhangs have something to rest on as they are being printed. The supports and rafts can be cut away from the final product after it has finished printing.
Printing and General Maintenance
- Do not set the extruder temperature too high or it will reduce the coefficient of friction on the filament and the stepstruder to a point where it cannot extrude anymore.
- Makerbot people recommend cleaning the printer after about 50 hours of printing or so
- If your model has trouble sticking:
- Clean the plate.
- Make ABS goop and paint a thin layer on, this will help the filament stick to the plate more easily.
Post-Processing
Turn off the printer and take your print off the plate. Depending on the surface area covering the plate this could be difficult, easiest to wait for the plate to cool completely. Gently use a flat head screw driver if necessary, be sure not to rip the kapton tape. With a knife or razor you can trim down the sharper edges if necessary. If there are tears in the model that might compromise the integrity of the model you can use acetone to weld the model back together. You can get acetone from the chemistry department.
