Meet Loki, my small dog.  As a responsible dog owner, I carry a pack of dog walking bags with me when we are out and these are housed in a very popular, capsule-shaped container that screws together in two halves. The problem is that the screw fitting only has about 1 ½ turns of travel and easily comes undone when you are not looking so you lose half the container and its contents without realising it. Surely there is a better way…?

The Challenge

To improve on this popular design, I decided to take advantage of the new opportunities that 3D printing opens up. Design for 3D Printing (Df3DP) enables you to think outside the box and removes obstacles to new designs without compromise. So…

• Making the component in one piece would remove the necessity to assemble parts after building and losing half of the carrier and its contents would be a thing of the past.
• The part has to be robust as these things get thrown onto the car, dropped, chewed, sat on etc.
• It has to be functional. The container has to be attached to a lead/belt etc and needs a hook to securely attach (but not too securely) “used” bags for disposal later.
• Like every product these days, it has to feel right.
• It has to be low cost to make.
• The ability to customise the part would be very useful.

The Design

The Formlabs Fuse 1+ 30W was chosen as a starting point for this job for a number of reasons:

• The range of robust materials available. Nylon 12 was chosen for this job.
• Part cost is very low as there is little waste.
• The machine is capable of printing assemblies with moving parts, in one piece.
• Df3DP opens up a number of avenues. As engineers, we are taught to design our object and then ask ourselves, “can this be made?”, and this is where the compromises start. Tool clearances, draft angles, flow dynamics, heat distribution etc. All of these things and more have to be taken into account and allowed for in the design so it no longer resembles the designer’s initial intent.
• Df3DP gives almost complete design freedom. Let’s start with the original problem of making an object that won’t fall to pieces. Printing on the Fuse 1 allows moveable hinges to be printed already assembled and they won’t come apart.

So what are the benefits of using Df3DP and the Formlabs Fuse 1+ 30W for this design?

• The holder is printed in one piece including the hinge. No more returning home with half a container!
• The finished item is robust and tough and should last years.
• Low cost. The amount of material used means that the cost is less than £3.
• Fully customisable. A couple of minutes in CAD and you can add your dog’s name at no extra cost. (Useful if you have multiple dogs with different bag sizes etc.)
• Made from renewable material (Nylon 12), so my dog feels a bit less guilty.
• Multiple design iterations can be run simultaneously, cutting times to market.
• Parts are tough enough for end-use applications such as this and with the full build volume available, small to medium manufacturing runs are possible without expensive tooling.
• All parts in a build can be mass customised: names, reseller logos and other mods etc.
• Movable assemblies removes costly assembly time and potential for failure.

About Formlabs Fuse 1+ 30W

The Formlabs Fuse 1+ 30and its integrated Sift station are a compact SLS system that can produce high quality, robust parts using any of 3 materials (more being added in the months ahead). Materials include:

Nylon 12 – General purpose, all-rounder.

Nylon 12GF – Glass filed Nylon 12 offers greater stiffness and better stability for parts subject to raised temperature.

Nylon 11 – Offers better impact resistance than Nylon 12.

The Sift station ensures that unfused powder from the build is sieved and recycled for future prints, minimising waste. The de-powdering process and general powder handling is simple and clean.

Go to the Fuse 1+ 30W page

Send us a file and we will be happy to print it for you –  see for yourself what this machine is capable of!