Orbex cuts part setup time by 90% and succeeds in right-first-time machining using innovative CNC metrology

Products used

Background

Founded in 2015, Orbex is a UK-based orbital launch services company, serving the needs of the small satellite industry. Orbex has a strong focus on quality and sustainability and works with suppliers that help with process optimisation and automation to achieve this goal.

Orbex has developed one of the most advanced, low carbon, high performance micro-launch vehicles in the world. At their production facility in Forres, Scotland, the company manufacture the carbon-fibre structures and tanks for these launch vehicles, taking control of part layup, machining, and inspection.

As Research and Development started for the part design and manufacturing process, Orbex quickly realised their traditional method for aligning parts would not be suitable for the nature of these components, and, as a result, the parts would not be trimmed accurately.

Challenge

Orbex was heavily restricted by their traditional alignment method and its lack of suitability for the complexity of their Payload Avionic Module (PAM) as Gavin explains: “Our original method involved relying on the orientation of the jig to align the part. It wasn’t optimal but it was sufficient for aligning simplistic geometric shapes like circles or squares. As soon as we started working with odd shape parts, planes, multiple ribs and pockets, it quickly became clear this method wasn’t going to give us the right level of accuracy”.

The inherent challenges of composite materials also caused issues in the alignment process, as Gavin discusses: “The PAM is a thin-walled part, and the layup is delicate in places. As with most composite parts, there’s also a risk of distortion and the parts don’t come out exactly as you hope, making it a challenge to know exactly where to machine”. This variability and inability to account for the distortion had caused windows and pockets to be machined to incorrect sizes, leading to issues in assembly when the metallic modules did not fit into these apertures and had to be reworked.

Gavin continues: “It was also a labour-intensive, ‘time-hungry’ process. Aligning the part would involve shimming the part up to get the faces correlated, manually clocking it or measuring with just the probe to get the alignment as best we could. The PAM is a multi-faceted part with lots of webs in it, plus the central axis of the vehicle runs through it – trying to best fit align the part using these methods would take significant time”.

It was taking Orbex a minimum of 5 hours to set up the part and this loss in time was being effectively doubled due to the multiple machining operations required. Furthermore, the lack of automatic validation was costing more time. Gavin explains: “We’d rely on the measurements we’d taken and, in some cases, would machine the pockets small, check they were in the correct place and then recut them, which was obviously very time-consuming”.

Solution

Due to the small number of parts Orbex had available and the importance for right-first-time machining, MSP recommended the implementation of its full MSP PerfectPart suite of metrology products; products designed to remove errors from part processes and stop the surprise of parts failing inspection. In addition to providing Orbex with a solution for aligning its complex parts, it would also ensure any errors within probe setup and calibration and within the CNC machine would be accounted for, increasing confidence across the manufacturing process. This starts with AutoClock and NC-Checker to ensure the probe and CNC machine are setup and error-free. AutoClock was implemented to enable Orbex to gain an accurate measurement of the sphere position which is then automatically uploaded to the work offset on the controller. It removes the risk of human error from occurring, rippling throughout the rest of the manufacturing process and affecting the finished parts.

NC-Checker automatically follows to calibrate the probe in 5-axis and then assess the geometric performance of the CNC machine tool to confirm if the machine is capable of machining a part to within tolerance. It performs a variety of rotary and linear axis checks and, on completion, produces a ‘Benchmark’ report to clearly show the probe and machine’s performance and highlight areas with errors so these can be resolved before machining begins.

The products together take around 30 minutes to complete via a single program, making it viable as a standard operating procedure as Gavin explains: “At the beginning of each week, we’ll now run this pre-checking routine on our CMS Ares machine. It’s such a simple thing to do, any of the operators on the shopfloor can run it.

To solve Orbex’s part alignment challenges, the next product from MSP’s PerfectPart suite, NC-PartLocator was introduced. NC-PartLocator is better suited to aligning complex, distorted or thin-walled parts than traditional methods.

The software measures the part using 5-axis probing and automatically generates a best fit alignment in 6-degrees of freedom. By generating the alignment in this way, the software can compensate for any discrepancy between the physical part location and the nominal machining program, for example, when distortion has occurred. An alignment is generated based on where the part ‘really’ is inside the machine. The updated alignment is automatically uploaded to the controller, no additional machining program edits necessary, and any misalignment errors are automatically removed.

Gavin advocates: “Generating alignments in this way takes a lot of the stress out of it. You can trust that everything is aligned as it should be, so when you press the Go button, you can see the alignment coming through and know you’re going to get out exactly what you expect. And the speed with which you can have everything set up - it’s definitely made life easier”.

Result

Implementing AutoClock and NC-Checker generated results immediately, showing an error in the machine the first time the products were run. Gavin explains: “The first Benchmark flagged an issue in the C and B axis which could have caused some of the holes on the outside diameter to have been misaligned. The report really helped the machine tool vendor drill down into what the error was likely to be and rectify this before machining began.

“Having this knowledge saves time, resources and increases our confidence”.

Before introducing NC-PartLocator, Orbex’s part setup routine was taking around 5 hours each time. The software’s ability to automate the part alignment process has reduced this to a stable 30 minutes – a saving of 90%.

“The software has also removed a lot of the variability out of the process for us. Before, I’d try and set it up as quickly as I could, but it wouldn’t always go to plan. NC-PartLocator takes the same amount of time each time, giving me a more definitive time frame and the ability to create a schedule to deliver my parts on time to assembly”.

Orbex now also has an improved fixturing process because of NC-PartLcoator, as Gavin explains: “Rather than having to dowel everything down and really constrain the part, we’ve been able produce a much simpler fixture and use MSP’s software to best fit align the part instead. We don’t have to skim the fixture each time, we can use the fixture as it is, and the alignment will come in and work out what it should be. It’s a much simpler fixturing process and saves us lots of time and effort”.

Orbex initially approached MSP to solve their alignment challenges, however, the product has brought about unexpected benefits to other areas of the business. Orbex has been able to integrate NC-PartLocator’s data into the layup projection process. A new tool had been created which used spherical targets but Orbex were unable to see where these targets were sitting in relation to the mould.

This process has been transformed as the team now use NC-PartLocator to find the position and feed this back into the CAD.

Most importantly, the MSP PerfectPart suite has removed the guesswork and risk out of the machining process, something Gavin values greatly: “The whole package is a no brainer really. The risk reduction when machining such a high value part cannot be understated. There is no room for error, so being able to make the parts right-first-time has been a huge success and increased our confidence significantly”.

Future

As Orbex’s launch date looms, Gavin is looking towards the future: “The time savings will be absolutely critical as we ramp up production and the amount of parts we’re making increases dramatically. We currently only have one machine, so because we’ve essentially increased its capacity with MSP PerfectPart, it’ll ease any bottlenecks”.

Introducing MSP within the Research and Development stage has been integral to defining a process Orbex can use to keep quality consistent as production starts and more personnel become involved.

“When we do decide to buy more machines, the simplicity of the MSP package means we’ll be able to just drag and drop that process onto another machine”, Gavin comments, “By introducing it as part of our R&D process, we’re already familiar with the software so we can transition into production easily, keep quality high, and hit the ground running straight away”.

Gavin also has plans to use MSP PerfectPart to produce other parts: “We’ll definitely be using it for the Pressure Vessel Mounts and the Fuel Tank End Caps. The latter are quite critical as it’s not possible to measure the part’s two faces at the same time but you need to know if they are parallel; NC-PartLocator’s data shows this.