3D Printing - 'rafting' removal: back to basics

Above: Design as printed.

This is intended as an explanation for the term of 'rafting' that is frequently discussed on this blog.   

This is part of the 'beginners guide to 3D Printing' which is aimed at teachers and students who are printing for the first time or looking at different aspects of 3D Printing.

On the left is a basic 'Unicorn' design.  The design is freely available on Tinkercad, and is public domain.  It is 70mm across, 60mm high and 30mm across.   This is the design as shown straight after printing with all of the 'rafting' still present on the design.  Generally the teacher in the classroom removes the rafting himself, as it at times can be somewhat difficult for students (particularly the younger students) to remove the rafting without damaging the print.   This depends on the print itself and the details of the print, an object that has thin and detailed parts can sometimes require particular attention to remove the rafting.   In the case where the rafting is broken it tends to be repaired with superglue when it is possible. 

Left:
The basic tools to remove this rafting that is used by the teacher is a basic pair of pliers with a cutting edge to them.   The second key tool used is a small screwdriver with a 80mm length and a width of 3mm.   This tool is key to removing small amounts of rafting in delicate locations which cannot be generally removed without causing marking or damaging onto the print itself.

Left: 
The breaking of the rafting around the head of the unicorn and the base of the unicorn.  This has been completed by using the pliers to break the rafting and then wedge out the rafting using the screw driver.

Left: 
The removal of the rafting is nearly complete.  Particular care has to be taken around the wings of the Unicorn as it the connection between the wing and the body of the Unicorn is only 2mm thick at the place where it joins.  This typically would be an area where we would experience 'breaking' of the print.   The tail can be seen with particular care needed to remove it without it breaking.

Left: 
The removal of the rafting is now complete.   Despite all due possible care one of the wings of the Unicorn has detached from the print.   At present there is considerable rafting waste from the print which needs to be disposed of.  This is part due to the design, which the head has produced considerable rafting as part of the design, some of the more rectangular objects produced have little or no rafting.   The wing will be attached with superglue prior to printing.

3D Printed Stand - Recycling Projects

Above: Project shown from above

Challenge: Student was challenged to use a previous print, that had not be successful and create something individualised, that had a purpose.   The student choose initially to select the base of the 3D Printed Glow-In-the-Dark base.   Student then choose to mount two unicorns on the base.  Student is nine years old.
Background: One of this students first print was the Glow-In-the-Dark horse, featured on this site, which was a single print.   The  student had been extremely pleased with this, however there were some issues with the strengths of the legs, which were particularly thin.   The student lost the model as the result of an accident and as a consequence wanted to do something proactive with the base.  Given that it was glow in the dark filamaent, the student decided to mount regular PLA printed objects or designs on the base, with the intention that the base would create a glow, which would be then reflected by the objects on top, hence white was choosen for the design.  The unicorns were sourced from Tinkercad and were not designed by the student involved.   They were choosen by the student

Above: Unicorn shown with foot of horse visable,

because they had a squat flat base, which the student felt would prove more stable than the previous design. 
Level of Difficutly: Low - the student was not directly involved in the creation of specific parts of the design.  The base was a simple rectangle expanded, the Unicorns were sourced from freely available Tinkercad projects.  The student was challenged by the front of the design, in the earlier 'Horse' print the student had attempted to sink her name into the design of the plate.   Her solution to this was to produce a white filament plate to cover the space were the name had attempted to be placed.   The glow-in-the-dark filament is striking and effective however we have had issues withs detailing and finer points of design.  Because the details for the name was sunk into the plate the PLA could not really be removed to have a strong effect from the lettering.  Finally the hooves of the horse could not be removed completly from the base, we attempted to use sandpaper to remove them, however this proved to less than satisfactory and was not completed, the hooves were considered to be a minor issue as they are 1mm-2mm.

Timeframe: The total print time for this project was seventeen hours.   The two unicorns that were mounted on the base took five hours to print each.  The base was seven hours.  While the name plate has not been added to the project, the time for this is expected to be no more than one hour.
Size: The size of hte base of the plate for this print is a rectangle.   It has a width of 20mm.  It was 200mm long and 120mm wide.  The unicorns were 50mm by 50mm and 80mm high.
What we would do differently: The student was the driver behind this print, hence her desire to use the Unicorn prints and designs.  Ideally the student could have designed something original herself but she was intent on using the pre-designed Unicorns for the print.   We have had a number of prints this year that have not worked and are looking to use them in some way, another example of this has been the draws that were not size appropirate for meaning that new storage is created.
Next Steps for Students: To look to in ways to use prints that have not worked.   The student who is working on this is having the first year in the classroom using a 3D Printer,