The ARI technology group has made good use of its growing number of 3D printers for prototyping tasks - Typically when developing and testing instrumentation or small parts for the Liverpool Telescope. However, there are some tasks which require metal parts especially when strength or precision or stability over temperature range is required. 

Typically these parts are outsourced to a local machine shop supplier or passed onto the Faculty of Engineering & Technology workshops within LJMU. This can usually add a fair amount of time and cost when a quick turnaround is needed - especially when prototpying or when a part is needed right before a maintenance trip to the telescope.

Earlier in 2025 the team had an opportunity to bid for internal funding to procure a small 5 axis CNC (Computer Numerical Controlled) machine. This device is still much more expensive than a 3D printer even though it is a benchtop size however, it extends the teams capability a lot by allowing us to work with metal in house for small parts. Although 3 axis machines are more affordable, the 5 axis setup allows milling of much more complex parts. The learning curve is steep - especially compared to the 3D printers. However, the team have been able to manufacture some useful parts already! 

The machine is a PENTA Pocket NC. It has a full simulation suite which allows the machining operations to be run virtually before actually cutting metal.  Adam Garner (NRT control and automation engineer) setup the machine and created some test parts before moving onto jigs to support the fold mirror gluing prototype work. 

The team realised that PLA was not a good material to hold the mirror pads in place as it contaminates the surface before the glue is applied. A strong glue bond requires a very clean surface to ensure correct adhesion.

Making a pad holding jig for fold mirror gluing tests on the Pocket NC - Adjusing the part between operations and showing lots of swarf from the machining process

A completed fold mirror pad jig part. A delicate facing operation is applied to carefully set the height the pad is from the mirror surface. This controls the glue thickness.

Using the freshly made jig part to position a pad during a gluing test - the jig and pad can be ultrasonically cleaned to remove dust, grease prior to gluing (unlike with the 3D printed PLA jigs)

The team hope to make more use of the machine over the coming months as more prototyping and instrument development take place.