Friday, March 22, 2019

3D Printed Animal Hay Feeder Model

Above: Original design with props.
Challenge: To create a farm accessory to work as a hay feeder.  The print needed to work in conjunction with a number of other items such as hay bales and model to scales cows.
Background: Following the success of the students who designed the four and eight calf feeder designs for the farm toy business the students decided that they wanted to target the next item on the list which was a hay feeder.  This involved creating a base with bars and a cage.   The students who designed this originally decided to create it as a single piece and as a result there was significant amount of rafting.  As a consequence the removal of the rafting was relatively difficult - there was a bar that was popped out when it was removed. The students were then faced with a challenge - how to produce the cage without having to produce so much rafting. 
Redesigned version with separate base and poles
 The solution which they came up with was producing the cage in stages, first as the base and the top, with the second stage being the base of the platform having holes in it which the poles could then be inserted into.   This was a slightly complicated process as it involved including the depth of the poles into the base etc.    However the students were able to half the printing time for the project and remove the need for rafting.   The students are again creating this prototype as a potential commercial project for a company that produces farm themed toys and sells commercially.

Level of Difficulty: High - this is producing a product that is potentially going to be made commercially and requires the base, base and top level to work in unison.   It has required considerable reworking to get the measurements and design to a point that it would be considered to be completed.   This has stretched some of the top design students in the classroom to their limits to complete it with the minimum amount of printing required.
Time frame:   The original design that was a one single piece design had a significant piece of rafting and had a ten hour print time (see photo left) the revised version with the students creating individual bars and a separate base and lid was five hours total for all of the parts of the project.   This second version has virtually no rafting and therefore would be the direction to move in the future.  The normal default settings apply as always, which is an 8mm nozzle and 20% infill.
Size: The design measure 90mm across and was 80mm deep.  The design was 60mm high and the top frame had a 10mm box design as its framing.  Relative to the design of the hay and other animals this fits perfectly with the expectations for the design.
What we would do differently: The students underwent an extensive revision process to get this design correct including considerable reworking, measuring and development.   Little additional design is required with the exception of a stand for the cage, as it has one in real life.   The students themselves were the ones that drove the improvement based around the printing differences between version top left (ten hours of printing and considerable additional rafting to maintain its shape and form).    The second reworking of the design and print involved the bar rods being printed separately and featured and insert in the base, you can see this clearly in the photograph of the print with the bar removed shown in the top right hand photo.

Left: The two designs side by side.   The ten hour version shown on the left, the five hour version, prior to the super gluing on the right. 

The two designs are nearly identical but the students by breaking the process down and printing as component pieces instead of a single block design have halved the time that is needed to produce the project and reduced the amount of PLA (plastic) used in its production by nearly half.

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