Complex mouldings -- just in time

Inside the two modern structures of the OMS-Besser Group on the easternedge of the Milan metropolis, the air is charged with the energy of a growing,dynamic business. OMS, which was founded in 1969 by the Maina brothersto manufacture injection moulds, recently moved into a much larger facility(3,000 sq m) to handle its growth. That facility is a few hundred metersaway from the plant occupied by Besser, the custom moulding part of thegroup. It has grown so much within the past few years that it hardly resemblesthe company created by OMS in 1974.

Group President Germano Maina says the synergy between the two servicesis obvious for the business, but the real reason for offering a completeservice, from idea to assembly, is the benefit to OMS-Besser's clients.Whether they are buying moulds, moulding services, or both, they benefitfrom the company's integration. Moulders know about mouldmaking, and viceversa, but while knowledge is good, the hands-on practical knowledge thatcomes from actual experience is better.

Besser is a diversified custom moulder serving customers in such marketsas appliances, automobiles, electronics, and telephones, in Europe andbeyond. OMS makes moulds up to 13 tons, mostly medium to large size. Ithas become a global marketer, and its moulds are running in North and SouthAmerica, the Middle East, and Asia. More than 90 percent of its mouldsare produced for other moulders. Maina believes that OMS-Besser was correctin deciding to offer full service because every day more manufacturersare discovering the benefits of outsourcing the latter stages of productdevelopment. When they do make that change, either partially or completely,they want a true design/production partner, one who can assure at the startthat there will be no problems later. OMS-Besser, with OMS serving as theprimary customer interface, offers any level of design partnering the clientwants.

Complete Design Service

OMS says design, far from being an optional service, has become anessential component of the total service expected by a manufacturer, equallyimportant as toolmaking, moulding, assembly, quality assurance, or just-in-time(JIT) delivery. Long ago, OMS realized that, yes, it could do excellentmoulding and make absolutely world-class moulds, but if it couldn't helpthe customer move the product past the idea or preliminary design phase,its production skills would go to waste. Clients, it says, want to outsourceequally to hold down their own costs and to gain the expertise of the supplier.They want to avoid duplication of expenditure, not to mention the well-knownproblems that are still all too common when product design is separatefrom mouldmaking and moulding. Long-term OMS clients have come to expecta complete production partnership from joint product development to finalpackaging.

OMS, which is nearing 20 years of computer-based design, now uses only3-D CAD/CAM to speed up and improve the quality of product development.It retains a pair of 2-D stations for initial intake of client designs,since 2-D design files are the most common form of client input. But forits product development and refinement, it wants the power and simplicityof 3-D. In 1979, after a thorough evaluation, OMS became one of the firstusers of Catia CAD software from IBM/Dassault. Because the group dealswith complex mouldings, it was very impressed with the software's powerin creating and working with various complex shapes and surfaces.

One of the most frequently used software packages at OMS is MoldFlow, tosimulate mould filling. OMS says there are cases in which it doesn't needto use mould filling simulation because of the company's experience withthe same or similar products. These are the minority, however, and forthe majority of jobs, MoldFlow is required. Its main value to OMS is notavoiding problems, though that is certainly important. Optimizing moulddesign and, therefore, making subsequent production more error-proof andcontrollable is the chief benefit of simulation, says OMS.

As part of its commitment to clients, OMS has made significant investmentsin its internal 100 Mb/second Ethernet-based network. Recently upgradedwith high-speed, intelligent servers and routers, the network keeps productand mould designs in the digital domain from first input through design,modifications, creations of NC files for the machine centers, and productionof the mould. This eliminates the possibilities for errors as a file istransferred from one system to another, or from digital to physical form,and it allows for maximum speed and control. The recent introduction ofhardware intelligence also supports higher speed since the network is nowable to automatically give priority to more heavily used channels and toactively manage the overall traffic flow. Not only is the network organizingand prioritizing its own traffic, its fault detection systems are makingit more reliable.

Constantly Upgrading Tools

OMS began as a mouldmaking business and has worked constantly at whatit describes as a never-ending, expensive task: staying current with machiningtechnology. When IMI visited the plant, the company had recently commissionedits largest high-speed (35,000 rpm) machining center with automated toolchanging, this one supplied by C.B. Ferrari. It is now possible to do somejobs in one hour that formerly took 10. But that's not the only advantageof these new tools, nor is it what justifies the recurring investments,says Giacomo Maina, who is responsible for the CNC machines and NC programming.The real justification, he adds, is that with these machines, OMS can dothings for customers that could not be done before.

OMS did not start out to become a specialist in a particular market ortype of moulding. Now, however, it clearly has a majority of its projectsin the appliance, communications, and electronics/electrical componentsmarkets for customers like AEG, Sanyo, Philips, Siemens, and Moulinex,among others. And it works hard to stay current with those markets. "Interms of the moulds we build," says Antonio Baggi, OMS marketing manager,"we have developed a specialty in designing and building moulds forcomplex parts, and for moulding them." OMS has always had the skilledpeople and the advanced machines needed to make the complex moulds. Asit completed projects with thick and thin sections, hidden undercuts, multiplecore pulling, and microscopic tolerances, more continued to arrive. Thusit was the customers, says Baggi, who said this was OMS's strength.

The high percentage of moulds that are complex accounts for OMS's varietyin types and sizes of machines, including high-speed CNC milling centersand wire-cutting and spark-erosion EDM machines. The newest machines havea computer mounted in the controls, and all the machines have RS 232 connections.That means that there can be a PC at any of the machines to send informationback to the design department for corrections and improvements. In termsof size, the majority of OMS moulds can be classified as medium to medium-large.The company has the capability to produce moulds weighing up to 13 tons.When IMI visited, it was completing a new area adjacent to the mould assemblyroom where three injection machines will be doing mould trials full time.

Technology with Craftsmanship

In OMS brochures, one sees the expression "people + technology,"and the mouldmaking area exemplifies that philosophy. OMS has it own apprenticeshipand training programs. It is strongly committed to maintaining a high levelof craftsmanship among its technicians as part of its competitive advantage.It believes that a beginning machinist can't go straight to the computercontrols without first thoroughly understanding what the machine is actuallydoing when it is cutting metal. There is another room of machine tools,some of which are also CNC controlled, but all of which are smaller, andmade to be used by a craftsman. And as OMS notes, it will be a while beforea machine can assemble a mould and check to see if everything fits togethercorrectly.

Is OMS reluctant to give up the "old" technology? No, definitelynot, and one look at the new machine tools proves that. Rather, it's aquestion of appropriate technology, both in terms of the cost of the workdelivered and of the final quality. The simpler machines are often precise-lywhat is needed to do the job correctly at the best possible cost to theclient.

The newer machines enable OMS to answer the demand for increasingly complextools at a reasonable cost. Giacomo Maina sees a process of evolution atwork: product designers learn they can create more complex mouldings, sothey do. Then they learn from that experience and the next design is evenmore complex, and so on. The newer high-speed machining centers that canwork at 40 or 50 m/minute within very close tolerances allow those complexmoulds to be made at an affordable price, provided, OMS engineers say,you have the know-how to exploit these machines' potential.

Pointing to a family of moulds OMS made last year for a vacuum cleanerhousing, Giacomo Maina says that these parts are extremely complex becauseof the multifunctional design. The high-speed machining stations were ableto reduce production time by at least 70 and as much as 80 percent, comparedwith previous generation machines. But that, Maina points out, is not halfas impressive as the fact that as recently as five years ago these mouldscould not be made at all--or they would have been made in so many piecesthat manufacturing costs would have been prohibitive.

In another case, an established customer had a pressing need to bring anew air conditioner to market fast. OMS was able to go from 3-D designfiles of the exterior surfaces to moulding production parts from a familyof 18 small and four medium-large moulds in 72 days. The internal designof the parts was done by OMS with the client. That, OMS says, is not somethingit wants to do all the time, but when a good customer has a real need youhave to react.

OMS has also seen a rise in the requests for hardened steel moulds. Thelogic is simple: complex moulds cost more, so the manufacturer can justifythe hardening investment by making quality mouldings over a longer mouldlife cycle. OMS's tempering ovens are adjacent to the mouldmaking area.

JIT Moulding from the Start

When OMS created Besser in 1974, the intention from the beginning wasto provide JIT injection moulding to clients who were working with OMS.JIT is therefore the basic concept of production and Besser is organizedaccordingly. The finished goods warehousing is designed for throughputof material rather than storage and has a computer-based control systemtied to the central computer system.

There are now 37 injection moulding machines within Besser, ranging insize from 25 to 1,500 tons of clamp force. Most are robot equipped to facilitatethe around-the-clock production that takes place from Monday morning untilSaturday evening. The machines come from suppliers including Arburg, Negri-Bossi,and Remu. For Besser, choosing a machine supplier is not something doneonce. It depends on the technology needed.

Recent machine additions include a number of Mannesmann Demag Ergotechmachines, including a separate production unit in a room adjacent to themain machine hall. Seven machines (six 100-ton and one 150-ton) are makinga family of electronic parts plus other mouldings around the clock. Theyare fed by a centralized material handling unit from Piovan and each machineis equipped with robotics from Piovan+Star. This production group was createdfor products with relatively long runs, so it is designed for minimum operatorintervention. Generally, there are only two people in the room and it isalso used in a "lights out" mode on certain shifts. The systemincludes auto sprue cutting and automatic recycling of the waste throughgrinders.

Building on the Concepts

The OMS-Besser Group is taking steps to ensure that growth continues--ata sensible pace--in both production units. Since start-to-finish supportand just-in-time delivery make sense to clients, it is maximizing thesestrengths. When IMI visited, several offices in the OMS building were beingremodeled. "That is because customers often stay with us during thedevelopment process," explains Baggi. This is something we encourage,so naturally we want them to have a comfortable, functional office spacewith computers, fax, telephones, and so forth."

In the moulding operation, the group is thinking about a change to fourshifts of six hours each to broaden production flexibility and give employeesmore choices with their time. The group has had its own delivery trucksfor some time to make sure that products reach customers just in time.As for the facilities themselves, there are signs throughout both buildingssaying that being clean and organized are essential to the success of thebusiness. Judging by what IMI saw during its tour, either the signs workor the company really doesn't need them.


Contact Information
Antonio Baggi, Marketing Manager
OMS dei F.lli Maina Spa
S.P. Rivoltana, 46/48
20060 Vignate (MI)
Italy
Tel: +39 (2) 95931 1
Fax: +39 (2) 95360764