TFDL Makerspace Training
Self Serve 3D Printing
What is 3D Printing?
The term “3D printing” covers a variety of processes in which material is joined or solidified under computer control to create a three-dimensional object, typically adding material layer by layer. In the past, the technology was only useful to create prototypes, more properly termed “rapid prototyping”. Now, the precision, repeatability, and material range have improved to the point that some 3D printing processes are considered viable as an industrial production technology.
The 3D printers in Labnext use an inexpensive 3D printing process known as Fused Filament Fabrication (FFF), or Filament Freeform Fabrication. This process uses a continuous filament of thermoplastic material.
Two other popular technologies are Stereolithography (SLA) and Selective Laser Sintering (SLS). These two technologies are not available in our makerspace.
All 3D printed parts start with a digital 3D model.
In order to print an object, you first need a 3D model.
The following software can produce .STL models for 3D printing:
- Rhinoceros 3D
- 3DS Max
- Cinema 4D
- Fusion 360
In addition to designing your own models, there are several online digital repositories of 3d models available for printing. The most popular is https://www.thingiverse.com/
In the Lab NEXT makerspace, it is not permissible to print any models which are unsafe, harmful, copyrighted / prohibited by law, or intended for commercial use.
Models should be exported in .STL or .3MF file formats. They must be properly joined without any construction issues.
STL files describe only the surface geometry of a three-dimensional object, without any representation of color, texture, or other attributes common to CAD models.
To prepare a model for printing, it needs to be “sliced”. Slicing subdivides the model layer by layer, and saves them as machine instructions for the 3D printer. The file format of these instructions is .gcode.
How to Slice a Model
The Prusa MK3S comes with free open source slicing software called Prusaslicer. Prusaslicer is installed on a workstation within the makerspace. To slice a model, open Prusaslicer and follow the steps below.
- Drag in or Import your .STL or .3MF file (File>Import)
- Your file will appear in the middle of the digital surface
- This is a tool bar to move and place the model in space.
- This is a tool bar to access view, copy and undo tools.
- This section determines print settings, such as infill percentage, brim, and support.
- You can switch from regular “Model” to “Sliced” view for a preview of the print.
- Save your G-code file on your SD card.
- If you do not a have a card reader or SD card, you can borrow one from the Labnext service desk.
- The slicing software (PrusaSlicer) is available in the Makerspace. It is also available for free from prusa3d.com
- Changing slicing settings may change the support material, time and filament required.
Most settings for the print can be modified using the options on the right side of Prusa Slicer (located at 5 in the above image)
The print settings menu option is where you can select factory default templates. The primary difference between the print qualities is layer height. A higher layer height greatly improves print speed at the expense of print detail. .15mm layer height will meet most needs.
We only allow PLA filament in Lab NEXT's makerspace. The filament is provided free of charge and is available for use within the makerspace. The filament settings within Prusaslicer should be set at "Prusament PLA".
The printer should be set to “Original Prusa i3 MK3S”
One limitation of 3D printing is that you cannot print in mid-air; each layer must be supported by either the previous layer of the model, or by scaffolding known as “Supports”. PrusaSlicer will automatically determine the best location for support scaffolding. Turn on Supports to view this tab and select the option that best suits your model. Support material can be easily removed using your fingers or hand tools. You can sometimes avoid having to use support material by re-orienting the model so it prints at a different angle. For example, the "T" below could be printed without supports if it was printed upside down, and all of the models would not need supports if they were printed flat instead of standing up.
Common infill densities are between 20% - 25%. This offers a nice balance between durability and material consumption. If strength is less important to you than cost or time, the best infill range is between 10% - 15%. Even at 100% infill, 3d printed PLA parts should not be used in applications which require high strength.
One of the most common causes of print failures is low bed adhesion. The Brim function is used to increase bed adhesion. It is a widening of the first layer’s circumference. A brim is generally used with objects that have a small contact area with the bed, or on sharp-edged shapes to protect the corners from warping. A raft is similar to a brim, but has increased thickness and also travels completely under the 3d printed part. Both are easily removed after the print is complete.
After pressing “Slice now”, you will get estimates for printing time, cost, and the amount of filament used.
Prepare Your Filament
You may only use the filament provided by staff in the makerspace. Any user supplied filaments are not permitted.
Make sure the filament does not have knots. You can prevent these by securing the filament into holes on the spool. NEVER allow your filament to knot itself.
Trim the end of the 1.75mm PLA filament. Do not use any part that has been melted or badly bent. Tools for the 3D printer are in the 3D printer rolling cabinet. This cabinet is located below the PC for 3D slicing.
Before printing anything, make sure you have enough filament. You will get an estimate of how much filament will be required when you slice your model in PrusaSlicer. Be sure to leave a small buffer (5%) for any margin of error in the software’s slicing estimate.
When placing the spool on the machine, make sure the spooled filament rolls over the top towards the front of the spool, and then down towards the filament feeder.
Make sure your filament is secured when it is not in use. Not securing the filament can lead to accidental knots, which cause print failures and can damage the 3D printer.
Prepare the Prusa MK3S 3D Printer
The Lab NEXT makerspace uses Prusa MK3S 3D printers in the makerspace. While there is room for 2 different spools of filament, only one can be used at a time, as our version only has a single extruder.
3D printers are not bookable, so arrive with sufficient time. Remember, you get a time estimate when you slice a model in PrusaSlicer. Add 10% to this estimate to ensure your print will be done before Lab NEXT closes, as we do not allow prints to run overnight.
Insert your SD card. The slot is on the left side of the LED screen and the card must be inserted upside down. Do not force the card.
Gently wipe the bed with the paper towel and alcohol provided. Ensure the paper towel is lightly damp, but not dripping or soaked. Wipe only the bed, nothing else. Do not add any glues, hairspray, or other adhesives to the print bed.
Turn the machine on. The switch is in the back lower right corner of the printer. The LCD screen will light immediately.
There are only two buttons. They are both located to the right of the LCD screen. The Control Knob functions as both a button and a dial. It is the only button you need. Do not press the Reset button below the Control Knob.
Rotate the Control Knob until you find the option “Autoload filament”. Select it by pressing the same Control Knob. Follow the instructions on the screen. When loading filament and during printing, the extruder will heat the end to temperatures over 190 degrees C. Do not touch the extruder during printing or when loading or unloading filament.
Scroll down until you find the option “Print from SD”. Find your .gcode file and select it. The bed and nozzle will start heating immediately, and then your print will begin.
Watch the first few layers closely to ensure your file is printing normally.
Do not leave your print unattended.
Once your print is done, allow the print bed to cool for 5 minutes. This makes it easier to remove your model from the print bed without damaging either the model or the printer. It is especially important to allow time to cool to ensure the print bed does not get scratched.
You can unload your filament by selecting “unload filament” using the Control Knob. You must wait while the printer prepares to unload. Do not leave the 3D printer after selecting “unload filament”, as the filament should be removed immediately when the printer instructs you do so.
Once your print is complete, remove the magnetic PEI sheet and flex the sheet slightly to remove your print. Carefully remove any remaining PLA from the sheet and place it back on the print bed. Be careful replacing the sheet, as the magnets can cause the edges to pull down and pinch fingers.
Clean up any remaining debris or plastic. Please leave the space cleaner than you found it.
If a print fails: Immediately stop the print using the control knob on the printer and selecting “stop print”, and locate a Lab NEXT staff member. Do not attempt to clean any plastic off of the extruder. Depending on the severity of the failure, improper attempts to remove the failed print can damage the extruder or sensors.
In most cases, our 3D printer can print an overhang with an angle less than 45° without requiring additional support material. When printing overhangs, reducing the layer height can improve the print. For example, reducing the layer height from instructs the printer to produce more layers, allowing the printer to take smaller steps when creating an overhang. For angles greater than 45°, you should turn on supports when slicing the 3D model.
A brim will reduce the risk of lifting from the bed when a model has a comparatively small surface in contact with the bed, or when the model may warp. Warping occurs when a print is large and thin.
Some printers use hairsprays, glue, or other adhesives to increase the bed adhesion of prints. The print bed on the prusa printers has a special polyetherimide (PEI) coating which helps with adhesion. DO NOT APPLY ANY ADHESIVES TO THE PRUSA PRINT BED. It will damage the coating and makes cleaning much more difficult.
Make sure filament print temperature is correct. Do not print at temperatures over 215 C.
Click to begin: 3D Printing Quiz
- Last Updated: Oct 21, 2021 2:17 PM
- URL: https://library.ucalgary.ca/makerspace_training
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