“As a company primarily dealing in traditional machining techniques, producing Steel and Wear Resistant components for the downhole drilling industry, we are very much at the opposite end of the spectrum in regard to 3D Printing processes and materials! However, through a series of projects developing prototype electronically activated downhole tools, we have often needed speedy turnarounds on intricate bespoke parts, which would be prohibitively expensive to get manufactured using the methods we are familiar with. Graphite have always given us great advice on staying within the limits of what is printable and the lead times that we need to be successful and stay right on the cutting edge of design.” – Robert Smith – Development Engineer, Cutting & Wear.
Cutting & Wear (C&W) are a long-standing Graphite customer, and have been utilising our knowledge and expertise for their Rapid Prototyping requirements for over 5 years. During this time, they have been working on intelligent downhole tool applications. One aspect of the design was originally modular and not very efficient, taking around a week to produce and still not being quite what they required. Fast forward 5 years, they are now able to produce the finished product using a 2-step process, which is much more time and cost effective, thanks to the potential of 3D Printed parts.
C&W found that one of the key challenges when building an electronically activated downhole tool, was connecting the electronic part with the activating part. Circuit boards need to be very well protected in a harsh environment such as a well bore, whereas tool activation has to happen in the thick of things. Routing wires is also fraught with danger – high vibration, changing temperature and complex paths to follow, all of which carry a high probability of damage occurring.
The initial designs used 3D Printed parts to ‘hold’ the wires, as shown below. However, the held wires would still need to be protected. This would usually be done by applying sealant over the top, which would have to be fully removed every time the tool was serviced – not an ideal solution.
The design then evolved to utilise self-contained wire looms which could be connected, disconnected and reused multiple times. The challenge then became – how to produce the looms? Electronics companies were not interested in small batch prototype work, so everything had to be done in house at C&W.
Their team then got in touch with us here at Graphite Additive Manufacturing, and we worked with the engineers to review and improve the designs, settling upon a moulding approach. Finding the right mould tool material for this part of the application was also vital. Our team advised that C&W should opt for our ceramic SLA PerFORM material. This was the ideal choice for this application as it has high accuracy, low shrinkage, is stable and temperature resistant. This material can also give an exceptionally smooth surface finish.
Once the steel parts that would surround the wires were designed, the channels for the wire loom could be extracted and used to layout a mould into which encapsulant and wires could be installed. The first mould designs involved pressing 2 halves together to form the encapsulation, as shown below.
Although this proved to be successful, moulding had to be done in stages meaning that the processing time to build a complete loom was very high. A revisit to the design was required.
The final and current design uses a double-sided one-piece mould for each loom, a first encapsulant layer for wire retention is produced initially – without the need for pressing, as shown in image 5. This layer is then put into the other side of the mould and wires/connectors are inserted. Then, a second encapsulant layer added, as shown in images 6 & 7. The completed looms can then be installed onto the steel assembly and held in place with further 3D printed brackets, which were produced in our MJF PA12 material. MJF PA12 was the right material selection for the brackets due to it being a robust thermoplastic that produces high-density parts with balanced property profiles and strong structures.
The team at Cutting & Wear are very pleased with their new solution for Wire Routing. Reducing the production time by more than half has made a huge difference in their efficiencies and saved the team a lot of time and effort. The newer design is also more robust and repeatable to better meet what is required of it.
They estimate that the labour required for production is now reduced by around 30% of what it was, alongside having to do fewer runs, saving over £1,000 per set. The likelihood of now having to scrap a loom is also reduced and the lifespan of the moulds is definitely longer.
Our team here at Graphite are always happy to help find practical solutions to problems like this one, and we look forward to working with Cutting & Wear on future projects.