A clear tooling challenge
07 March 2017
When high-end audio equipment specialists Rega, looked to move production of its acrylic turntable dust covers back to the UK, it specifically sought out a manufacturer with joint expertise in plastic injection moulding and tool making.
In its experience, quality issues are often resolved quicker when core capabilities are integrated under one roof. Rega are widely known for its award-winning amplifiers, speakers, cartridges and turntables. Its products are purposely minimalistic. Its philosophy to seriously streamline and strip out ‘the unnecessary’ is a design trademark of every Rega product. As the company states: ‘Mass absorbs energy, and lost energy equals lost music’.
When Rega first produced its dust cover 40 years ago, it consisted of a clear acrylic flat top and four sides glued by hand. This proved sustainable until orders tripled and Rega placed the production with a Danish moulder. Ironically, because of the simplistic design, moulding the dust cover has historically been problematic. To hide blemishes the cover was moulded in a tinted acrylic. After ten years and three tools, Rega decided to relocate production. Coinciding with the need for a replacement tool and a company policy to have suppliers on-shore, Rega set out to look for a manufacturing partner who would produce the dust covers to its exacting standards, and in clear. To quote Ky Gandy, Rega’s Supplier Coordinator, “Our dust cover vision breaks every basic design rule for plastic injection moulding. It has no draught, a major issue in de-moulding. It has sharp corners and edges, when rounded ones are obligatory. It is also made in clear material, demanding a faultless mirror-like sheen allowing no tolerance for imperfection.”
In the meantime, working with the existing tool was a struggle not least because of the design constraints but Rutland Plastics discovered that two processes in the making of the tool had been skipped: a). the tool comprises a number of plates and these had not been positively located (a design limitation), and b). the tool had not been hardened and tempered. Undergoing the full process is vital to achieving the level of clarity demanded by the customer. Further compounding the quality issues was the type of tool steel that had been used, it lacked the higher carbon rate suitable for the quality demands of this particular moulding. Seeking to improve the quality, the tool underwent additional surface work preparation; the steel was polished to a fine high gloss finish and this helped to deliver the quality standard desired, allowing for continued supply in the interim until the completion of a new tool.
A new tool
Leveraging technical resources across all departments, Rutland Plastics came up with a solution; a polystyrene material was proposed to replace the acrylic that would match the look and quality that Rega wanted to achieve whilst delivering cost savings. The design team instigated a number of subtle design revisions to the dust cover that greatly improved the manufacturability. The revised design was validated using a Stratasys Objet Connex 3D printer to build test samples. “Rutland Plastics’ ability to show the redesign vision in a clear tangible format was a huge bonus for us agreeing to the adaptations suggested by their designers”, confirmed Ky Gandy.
According to Carl Martin, Technical Manager for Rutland Plastics, “This new tool posed some specific challenges for our moulding department that we had to overcome to make the part. It has been a collaborative effort and one that has required a great deal of tenacity to problem solve. While the surface geometry is not particularly complex, we needed to avoid any visible lines or flow marks and produce the clear high gloss finish that we assured Rega would be achievable with the new tool and material”.
Skilled supply partners
Summarising the project for Rega, Phil Freeman Company Coordinator commented, “Rutland Plastics persevered where many would have thrown the towel in. The net result is a wonderful product and I am proud of what we have achieved. It is a special moulding requiring the specialist know-how and application that we found in Rutland Plastics. We are engineers, we look for equally skilled supply partners for difficult and advanced manufacturing. Partners that possess the expertise and the same passion for perfection are essential to our development projects”.
Rutland Plastics have always operated a tool room offering a comprehensive suite of tooling services from design, tooling modifications through to routine maintenance and refurbishment. In recent years the tool room has expanded and is now housed in a new bespoke 504 sq. metre facility. Investments into new machinery and technology have created a fully equipped tool room to include Machining Strategist software, a Vertical Machining Centre (VMC), CNC spark and wire eroders, and recently a Mazak Nexus 250-II CNC lathe, all of which allows Rutland Plastics to offer precision machining of complex injection mould tooling able to produce precise, high quality plastic parts.
“We believe that investment in the future is paramount to remaining competitive in manufacturing and the injection moulding industry specifically, and we not only invest in hardware but in people. On average, there are three apprentices at any one time working toward their qualifications with full support. This includes injection moulding as well as other engineering disciplines within our company”, added Carl Martin.
This year to date, Rutland Plastics has seen a 10 percent uplift in tooling orders. This continues the trend that other toolmakers are experiencing, particularly in reshoring tools.
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