Reducing 5 Axis Machining Errors To Near Zero

A UK based innovator and manufacturer of high-pressure compression technology, has greatly reduced scrap parts from their production process and increased their productivity, with the introduction of MSP's automated solutions to their 5-axis CNC machining process.

Vert Technologies, based in Edinburgh, specialises in the design and manufacture of the patented, high pressure, Conical Rotary Compressor (CRC) technology. This unique product, invented and developed in-house, is supplied to key sectors such as refrigeration, heat pump and gas compression markets.

The main USPs of this compressor technology are that it offers a compact yet scalable compression solution, capable of delivering high pressures in a single stage without compromising on noise levels. It was during continual production of the compressors that the company realised manufacturing was wrong in their machining process.

Finding The Cause of Production Errors

Vert Technologies’ main ambition was to find the cause of any errors in their production process to stop their rotor parts from being machined inaccurately, causing poor performance of the compressor. The company also wanted to reduce the number of manual procedures required, to improve accuracy and productivity throughout the production process.

Nicol Low, Chief Operating Officer at Vert Technologies, explains: "We were confident that improving the part location, and ensuring the accuracy of the machine tool was key to minimising non-conformance, but were unsure of how to best put that into practice. We hoped MSP could help."

MSP works to deliver high-accuracy automated machine-tool solutions to the manufacturing industry and have applied their precision measurement expertise to projects worldwide across various industries such as Aerospace, Formula 1 and Energy.

Before MSP's products were introduced to Vert Technologies’ process, a highly skilled operator would manually create a fixture, datum the fixture and machine the part. With a complex part design and limited metrology on the machine, this involved multiple steps and was extremely time-consuming to achieve the necessary accuracy. This, coupled with the human error caused by the manual elements, resulted in a vast amount of machine downtime and scrapped parts.

There was also no simple way to test or adjust the accuracy of their machines to ensure they were operating to a high standard, as it involved using complex machine kinematics and the use of advanced measuring tools before machining took place, increasing machine downtime even further.

"We were seeing issues on different parts that were being produced on the same machine, which led us to believe the machine wasn't working to the accuracy it should be. Producing simple conical and cylindrical test parts, without the complicated forms of the conical rotor part, showed there was an unaccounted for, taper along the Z axis of the machine tool. If the machine wasn't able to produce simple forms accurately, it was never going to produce a more complex 3D-part perfectly", explains Nicol.

PerfcctPart Suite of Solutions

To solve Vert Technologies’ manufacturing problems, MSP firstly looked to diagnose the machine problems and investigate why the 5-axis CNC machine tool wasn't capable of accurately machining even simple forms. To do this, the MSP engineering team installed NC-Checker software, part of MSP's PerfectPart suite of solutions, onto the machine tool. This software ensures the machine tool's geometric performance is accurate enough for the part to be machined correctly. It produces automatic ‘benchmark’ reports which pinpoint exactly where the machine is under-performing, allowing Vert Technologies to identify where any problems lie and rectify them before any machining begins.

Nicol explains, "The benchmarking of the machine functionality was great as it instantly showed us where our machine inaccuracy was, and showed how accurate it could be, if the machine was working to its full potential."

Next MSP focused on solving the company's fixturing and alignment issues to stop the rotors from being machined off-centre. NC-PartLocator software, from MSP's PerfectPart suite of products, was installed on the CNC machine using standardised nominal programs. Vert Technologies was now able to automate part setup and automatically calculate accurate alignments for each machining operation. This removed the need for time-consuming manual alignments and shifting of datums that Vert Technologies’ highly-skilled personnel had to perform to achieve the necessary accuracy required for their parts.

"With the introduction of MSP's 5-axis automation software, not only have all the manual steps been removed, but we can now check everything before cutting the part. This has resolved many of the problems that previously resulted in non-conforming parts," comments Nicol.

Non-Conformance Rate Goes From 25% To Near Zero

By diagnosing the errors in Vert Technologies’ 5-axis CNC machining process and automating each stage to remove the introduction of manual error, the company has seen their non-conformance rate go from 25% to near zero.

Before MSP's solutions were introduced, run-out of parts could be up to as much as 120μm, and over the required tolerance threshold to pass final inspection. This number is now down to as little as 25μm and well within tolerance.

Nicol says: "The higher noise levels and lower performance we had been experiencing with the compressors stopped once the MSP software had been implemented. Using NC-Checker to diagnose and rectify the issues on our machine tool has also meant the machine parameters are the best we’ve ever seen. To have the confidence that our CNC machine tool is accurate and the parts it machines will be within tolerance and repeatable every time is invaluable."

The automation has also sped up production significantly as Nicol explains: "Significant time was spent using manual methods of trial and error: making a part, moving the datum, checking it and measuring it, and repeating until the part was within spec. Using MSP, this process now only takes a few minutes".

Adding automation to the alignment process has also provided many other useful benefits for Chief Operating Officer, Nicol: "Having MSP, and the automation it provides in aligning the part, reduces the number of personnel and resources needed on the shop floor. Senior engineers no longer need to be involved day to day – production can be successfully completed by any of our operators."

It was extremely important to Vert Technologies that they retained production of their conical rotor part in-house and, by implementing solutions from MSP, this was achieved: "We strive to be experts in producing our rotors and by keeping our manufacturing capability in-house we are in control of the learning that went into making our parts accurate," explains Nicol.

And the future of manufacturing certainly looks bright for the Vert Technologies team, who's product is unique in the marketplace. "Our plan is to embed our technology into products such as heat pumps, HVAC, processed gas, gas capture and recompression equipment, where our USPs fit well with the end user requirements."

MSP has a long-standing reputation of saving its customers time and money. Margaret Toberty, MSP's Director of Operations comments: "We are delighted with the results Vert Technologies has achieved by implementing our solutions in their process. Advanced, automated CNC techniques are imperative to the success and future of the industry, and companies like Vert Technologies are ahead of the curve compared to some of their much larger peers. They have such a fantastic product and it's exciting for us to work with a small business like this who have such ambition."

For more information: www.mspltd.com

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