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Mould and die making, machining, CAD/CAM, software
News Release from: Pathtrace Engineering Systems | Subject: Edgecam
Edited by the Manufacturingtalk Editorial
Team on 11 December 2000
Edgecam links pattern maker to OEMs
With EdgeCAM, Midas can now integrate with OEMs in the development and production of moulded enclosures and casework requiring the generation of complex surface forms.
When Midas Pattern Company was conceived it concentrated exclusively on pattern making for the foundry industry Eleven years on, the success of the Bedford-based company is proven with 35 people and a recent move into new purpose-built premises
This article was originally published on Manufacturingtalk on 30 Apr 2004 at 8.00am (UK)
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However, traditional foundry pattern making now only accounts for 25 per cent of turnover following the development of a highly successful medium volume resin injection moulding (RIM) process.
Demand from a largely blue-chip customer base means that tooling development, production and finishing of polyurethane components now takes the lion's share of the business.
The decision, three years ago, to invest in an EdgeCAM off-line programming system from Pathtrace of Reading for pattern preparation has been an important contributor to its success.
Further reading
Edgecam sets program developments for 2000
A major development in the Edgecam portfolio is the launch of 'Solid Machinist' which will enable uses to directly machine Parasolid models inside the off-line programming software.
Directly machine Parasolid design models
EdgeCAM Solid Machinist for Parasolid from Pathtrace allows users to directly machine Parasolid design models such as Solid Edge, SolidWorks and other leading CAD systems
Stored tooling data improves CAM efficiency
Technology Assistant is the latest productivity enhancing feature to be included with EdgeCAM, Pathtrace's off-line programming software.
With EdgeCAM, Midas can now integrate with OEMs and industrial design consultants in the development and production of moulded enclosures and casework requiring the generation of complex surface forms.
A prime example is a microscope enclosure for Renishaw plc., which recently entered production.
It is built-up from three moulded resin components comprising a base, main enclosure and light-tight sliding door.
The mouldings are very complicated, having very few flat surfaces and incorporate a number of moulded-in brass threaded bushes in order to simplify later assembly.
Managing Director Alan Rance reflects: "Without our computer-aided engineering and our CNC machining facilities we could never have looked at this type of work.
By the same token, a customer like Renishaw would never have considered us as a supplier.
When we made the investment it seemed like a big step into the unknown for us and was our single, largest capital outlay.
Three years on, it has become an essential facility without which our company could not have exploited the RIM process to the extent that it has." The Midas touch, in this instance, has been provided by development of a mould making technique which uses a variety of different epoxy resins to build up a metalised resin injection mould tool.
Polyurethane mouldings are conventionally produced from either high cost, high quality aluminium moulds or from low cost, low quality elastomer moulds.
The problem with high cost tooling is that it can only be justifiable if sufficient numbers are required.
Even if low volumes are needed, the drawbacks of elastomeric tools is an inherent instability which makes them hard to justify.
Here, Midas was able to exploit a niche in the middle ground with its RIM tool which is able to maintain much of the cost and lead-time advantage of elastomer moulds but with a working life of up to 5,000 cycles.
Also, RIM Tools do not have the dimensional instability of elastomeric tools and provide a highly viable alternative to aluminium tooling.
Here, Alan Rance cites a prime example as the enclosure for Renishaw, which must not exceed a tolerance variation of + 0.4mm.
Midas RIM technology has proven to be very popular with a variety of blue chip OEMs in the scientific instrumentation and electronics sector.
Alan Rance explains: "These companies require a high quality 'designed' look to their products but volumes generally do not justify aluminium or steel tooling.
Historically, many have used fabricated metal enclosures which tends to restrict design options.
Our techniques provide an alternative and we have equipped ourselves to provide a turn-key service embracing mould design, mould manufacture, production and the finishing of the components".
Some of the RIM mould patterns are manufactured using conventional manual techniques.
However, lead time constraints, increasing complexity of the designs and the requirement by customers to supply designs in electronic form have made a CAE-based approach essential.
Here, Paul Stokes, Midas Pattern Company's CAE manager, who was recruited specifically to set up and run this side of the business says: "Prior to joining Midas I had several years 'hands on' experience of using Pathtrace CAM software in a toolroom environment.
Over the years it has developed into a very powerful system.
it was therefore a logical decision to install the same system here." He follows on describing how a number of reasons backed his decision.
"When EdgeCAM was launched it was one of the few 'proper' Windows hosted CAM products and Pathtrace were heavily committed to developing the system further," he maintains.
"However, though EdgeCAM was not totally dedicated to toolmaking to the extent that certain other systems were, it offered a far better general purpose capability.
Also a prime consideration for us was its cost, bearing in mind that we were also committed to purchasing a machining centre and ancillary equipment," he says.
As well as producing foundry patterns and resin masters for RIM mould tools, the facility is used to manufacture metal inserts, mainly from aluminium to reinforce delicate sections of tools.
In addition, having the equipment has allowed Midas to diversify into manufacture of metal tooling for gravity die and shell moulding applications.
EdgeCAM is an important and integral part of the computer aided engineering set up alongside SolidWorks and other powerful solids/surfacing packages that provides the prime facility for tool and pattern design.
The normal tool manufacture route is to input the customer's design into the most suitable CAD system such as SolidWorks, then develop the mould tool pattern around the product.
Split lines, cores inserts and loose pieces are all taken into account at this stage.
The tool design geometry is then seamlessly passed into EdgeCAM for generation of toolpaths and machining data.
Paul Stokes describes ideal aspects of EdgeCAM such as the facility to directly edit the component geometry.
It has the ability to generate 2-D and 3-D boundaries from surfaces which increases the scope for making alterations to the geometry without going through retranslation to the originating CAD system.
Likewise, EdgeCAM's Solid Machinist interface is an important feature when working with files from SolidWorks or other Parasolid or Acis-based modelling systems," he says.
Recent machining developments within EdgeCAM attract similar praise.
Paul Stokes picked out the latest advanced surface machining capability as being particularly useful.
"The combination milling facility, for instance, makes the machining of complex parts containing many features such as bosses and webs much easier.
Likewise, the option to apply boundary and depth restrictions to the model is extremely useful, particularly when the finished model exceeds the working envelope of our machining centre." He explains more detail: "On the Renishaw project we had to build-up the master for the enclosure in two halves, each with three horizontal slices.
We machined the bottom slice first, then added the next level and machined that.
The procedure was again repeated for the top level." "The advantage of doing it that way was that we were able to complete the part without using tool extensions and so maintain maximum rigidity and accuracy.
That allowed us to achieve a high standard of machined surface finish requiring little or no hand finishing.
By using standard length tools, we were able to optimise speeds and feeds," he maintains.
Every cutter path generated on the system is simulated on EdgeCAM's Verify module prior to being applied on the machine as cost and lead times cannot accommodate machining errors.
Aside from the core program preparation capability, virtually all of the 'peripheral' functions within EdgeCAM are highly rated by Paul Stokes.
These include the CAD translators and Code Wizard.
"When we have had a problem with reading third party CAD data, the EdgeCAM translators have usually been able to solve it," he says.
"Similarly, though we have not made extensive use of the Code Wizard, it offers high flexibility; if we ever needed to send CNC work out we could furnish the company with the part program and know it is right and suitable for the machine tool control system.
Overall I've been very pleased with the way that EdgeCAM has developed; the current version is highly compatible with the needs of the toolmaker but it retains that all-important general-purpose capability, making it very good value for money," he concludes.
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