Shall the twain meet?

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Magazine Article, Source : The Manufacturer
Zone : Innovation Design and PLM
Published : May 2004

In theory, product lifecycle management systems are an answer to linking CAD and ERP systems. But it’s not quite that easy, says John Dwyer

Twin pressures, from the arrival of new legislation and easier technology, might just be enough to force design and production to start pooling information. The legislation is the new group of EC-inspired laws which make producers of, so far, cars, and electrical and electronic goods responsible for their safe disposal or recycling at the end of their useful lives. The technology is computer-based product lifecycle management (PLM), which links together CAD, ERP and other systems to provide a database of information about a product at any time during its life.

If you are taking your first look at PLM, life is much easier than in PLM’s early days, when you had to buy a separate system then interface it first to CAD and then to ERP. As Nick Ballard, CAD specialist at industrial consultancy Cambashi, points out, for new customers, the integration problem between CAD and ERP has largely been solved either by the provision of PLM tools as standard in many CAD and ERP systems or, says Ballard, because “these integrations are often part of the installation or implementation contract.”

But there’s little doubt that manufacturers who haven’t started down this road have a longish journey ahead of them. Even when the technical obstacles to closer CAD-ERP union are overcome, the much larger cultural obstacles remain. Whatever the reasons, companies The Manufacturer spoke to at random would like this integration but had higher priorities.

At Dyson, for example, the Malmesbury, Wilts, company would like the CAD-ERP link to ensure ‘consistency of data’, reports design manager John Myers. Dyson does R&D on SolidEdge, designs its products on EDS Unigraphics systems and has a Geac/JBA ERP system.

As reported (TM nov03 pp36-39), Dyson’s PLM is its in-house new product development (NPD) system which allows users to enter and retrieve information through web browsers. This source of information replaces a multiplicity of Word, Excel and Access files. It’s particularly useful in helping designers find information that enables them to reuse parts or mould tools. But there is no direct link between NPD and the EDS Unigraphics or SolidEdge CAD systems. Myers says Dyson would like to develop an application that made sure the ERP and CAD of materials were in sync, particularly with engineering change orders.

The CAD system is updated long before the ERP system knows about them, says Myers, and he would like to devise a system that flags up in both systems simultaneously the fact that a change order has gone through.

Not far away, in Marlborough, Wiltshire, Microlights supplies lighting for shops and retail chains. Engineering manager Daniel King says Microlights has between 250 and 300 product lines, each available in a variety of wattages. The company will also supply products to order. King usually has between a dozen and 20 specials on his desk at any particular time. Shop lighting is a seasonal business – the rush comes when the shops are getting ready for Christmas from July to late October.

King says he would like to link Microlight’s Fourth Shift ERP with its Excitech-supplied Autodesk CAD system. He knows that AutoCAD can export bills of materials straight to a Microsoft Excel spreadsheet, and straight from that into Fourth Shift. But when he was appointed a year ago he found that the AutoCAD system had been installed without enough training. So until he can be certain that design files are being saved and recorded correctly he’d rather not take the risk of linking the CAD system to anything else.

Having said that, all the CAD product models are stored: “We have all the parts in a library on the CAD system,” he says. Every screw and washer is recorded, and the part numbers on the CAD files are the same as those used in Fourth Shift. At the moment, as soon as a model is created, “then we can manufacture the product.”

The bill of materials production uses is typed up manually by an engineering administrator. But the production ‘as built’ bill of materials and the ‘as designed’ bill are converging, because Microlights is moving towards configure to order. This means that packaging and other items that aren’t included in the design bill of materials won’t be needed in production either. The number of box sizes is being reduced from 40 or 50 to two or three and the packaging will happen automatically at the end of the line without a need for packaging to be allocated to particular products.

King would also rather control engineering changes and concessions – the allowing of substitute parts in a particular delivery to make up for shortages – manually to make sure they happen correctly. “Our way of doing it may not be totally dynamic but it’s working.”

Ian Chiddell in the R&D department of Pressure Seal, now part of Paragon Group, does provide bills of materials to production in the form of an Excel spreadsheet. But there is no link back from production to design: “In an ideal world,” says Chiddell, “we would like to have developed gradually to that.” But it didn’t happen, partly because of the takeover and all that happened round it.

One source of grief for all these users is that, though design authority may sign the product off on the CAD system, manufacturing have to make their own changes. Products go to the customer with a pack which includes a manual, software CDs, written notes in the right language and the right mains cable for the country the product is sent to. None of this will be listed in the as-designed bill of materials. Nor will the cable clips which hold the wiring harness in place, but all these items have to be listed for kitting the item for the shopfloor.

Production may even have to modify the design. It may, for example, find it has to split the harness in two to make the wiring fit into the unit. This pre-production work should be another design stage, with pre-production engineers finishing off the design on a CAD system. But few companies are happy to buy another £10,000 CAD workstation for pre-production work.

Even if they were, which CAD system would they use? It is increasingly difficult to talk about ‘the finished design’ when so many products are made up of a mechanical design, an electrical and an electronic design. The metalwork in a product might be designed on an AutoCAD system, but the printed circuit boards which fit into the metal cabinet are likely to have been designed on something else, and other parts might have been designed on other systems. Buying parts in from subcontractors adds another layer of complication.

The information has to flow the other way too. A key aim of PLM is to reduce redundancy and duplication in part numbers. So the design process should now allow designers to re-use as many existing designs as they can. But to do that they need to see what’s already been designed.

The ERP database should hold not just basic part information but enough extra information to describe each part well enough for the designer to recognise whether they can reuse a part or not. If they can’t find what they’re looking for in five minutes, says Doug Miles of ERP supplier Infor, they’ll design it from scratch because CAD makes it so easy to do. And the designers want to access the information from their own system. They don’t want to log into the ERP.

As Ballard puts it: “No two companies’ data structures are going to be exactly the same, and neither is the way that they enter this data. So some customisation will be needed to make sure these links are to work in any particular company.”

But he adds that these are purely mechanical issues about data transfer. They don’t deal with the knotty problem of making sure that the bill of materials the CAD department produces for a product is transferred to the ERP system in a form that the production department can use to make the product on the shopfloor. Design intent is one thing. Manufacturability is another.

From the outside, much of this seems to amount to the need to devise a business process. Making sure it’s adhered to is a cultural matter, and cultural integration, already an incredibly difficult trick to achieve, is made even harder in companies which have moved manufacturing offshore.

But other things intrude too. How well do any of these systems work separately? If you’re not happy with your CAD or ERP supplier, never mind which system they’ve sold you, you won’t want to integrate them with anything.

That’s an issue that IT suppliers should give more thought to.

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