Repairing a broken Toy

 

Challenge: To repair the broken part of a sandpit toy.

Background: We have a school sandpit, and in it we have a large number of high use items.  One of these is the bulldozer shown in the photograph on the left.  As shown the front of the bulldozer has broken off.  While this was a shame for the students it also allowed us the opportunity to use the broken toy as a discussion piece - could we 3D Print something to replace the broken part of the toy.

This provides a number of challenges - the first aspect for that is to build the replacement part that fits the size and shape of the digger, the second is to work out a way to attach the blade to the front of the digger.   We used a group of students to work in pairs on the project with three groups working to produce ideas that they could bounce off each other and then selected one to produce the first draft effort.

We come from a rural area of New Zealand and as a result the students live rurally and are involved significantly in dairy farming.  The students as a result have experience and knowledge of machinery, which in this task they were able to bring to the fore.  

The first attempt at a replacement piece is shown left, at five and a half hours it was considerable, but the challenge is in producing a durable piece, potentially an interchangeable piece and something to replace the broken piece.

Level of Difficulty: Hard.   There are a number of complexities to the print, while the blade itself is the key element the hardest part is making a connector for the back of the blade to the front of the digger.  The students have made a first attempt at this but they are looking at revising what has been made as they are not happy with the connection and then the subsequent operating of the digger.

Timeframe: As noted five hours.  We are now attempting to look at the connection (shown left) as the back of it needs attention.   Having printing the main part of the digger blade, we are now just focussing on printing the connection piece, this can be measured in short minutes (ten to fifteen).    We are going to concentrate on correcting this part of the print until it is perfect and then look at printing the entire project again from the start once the students feel that the can be successful.

Size: The blade measures 140mm long and is a basic shaped rectangle of 60mm by 60mm, hollowed so it is able to scoop.   

What we would do differently/next steps for the students: The students have already identified that they can make a range of scoops to go at the front of the machine, once they get the connection piece right.   Once they have mastered that we are going to be challenging them to 'brand' their machinery.  We have already attempted this in a series of prints from last year with a similar theme.  This project was carried out by a senior student - this project is being worked on by seven and eight year olds who are working with Tinkercad for the first time.