Die & Mould Sector

Moulding To Changing Time
The business of producing dies and moulds is a highly integrative effort involving machines, tools, software, and people.
Making moulds and dies is not just about cutting tools and scraping metal from work-blocks, but a careful combination of the process drivers. It is a team effort on the part of everybody that has enabled the die/mould making sector to face up to the challenge of demands of diverse natures from a slew of manufacturing sectors, and come out trumps. However, there are some loose ends still to be tied.Apart from integrated effort, individual initiatives in changing process setups in
mould shops, opting for high-performance tools etc, have also been instrumental in the success of the die/mould makers the world over.

If the diversities of demand across different end-user sectors is studied, the plastics sector stands out for obvious reasons - large variety of products, smaller product lives, and most importantly, the competition in the marketplace, where a new entrant in a particular category, needs to introduce new features into his product, to get an edge over the others already operating in the market.

Market Growth Scenarios
Many die/mould makers are keen on expanding their markets to other parts of the world, such as Southeast Asia and China. One reason is the burgeoning automotive sector, which consumes a hefty amount of dies/moulds for the fabrication of automotive parts. That is good news for die/mould makers in Asia and Australasia, as well as those in the West who have a market in Asia.

While on Asia, one cannot miss India. The ever-burgeoning auto components sector, whose exports rely a lot on good quality moulds and dies (zinc and aluminium alloy die-casting units are doing big business selling carburettors, automotive door locks, etc), on the one hand, and the cash-rich stainless steel utensils sector on the other hand, are driving the growth in the domestic die/mould industry. The dies used by the utensil manufacturers are typically those employed for bending, drawing and deep drawing operations. Considering the volumes of stainless steel kitchenware which emerge out of shops in the country, and also keeping in mind the tremendous export potential that these products have, this sector is certain to be a sustained area of
demand for die makers. A look at the variety of utensils – shapes and sizes – would set the mind racing to the innumerable dies that may have been employed to fashion them.
The small-scale Indian entrepreneurs who specialise in die-making, are now no longer plagued by the lack of finances.
Low-interest loans are there for the asking; for investments in technological upgrading at the die-making shops.
CAD/CAM software and CNC machines are now affordable, and the quality of these dies and the life thereof will also be improving, resulting in timely fulfillment of export orders.

Material Developments
For the plastics sector, it has been a case of ‘aluminium to the rescue’. Steel moulds are still common, when there is not much pressure on delivery times on the mould maker, and when the end-user is a small-scale manufacturer, whose output is limited by a modest demand for his products. However, when the demand in the marketplace increases, the moulds will have to be overworked.
Cost and functional superiority would be the guiding criteria that the mould maker would base his decisions on. The result: the steel may have to go, making way for aluminium alloys. The addition of magnesium, copper, zinc and silicon in varying proportions to aluminium, enhances its functional properties (while being machined, as well as while being used to mould the end products). The trigger here is the demand for a mould which will increase the number of products moulded every day.

Aluminium Economics
There have been total transitions of late, from steel-mould-making setups to aluminium-mould-making ones. Toolcraft Plastics of the UK is one of the latest to be bowled over by the advantages of aluminium. The said company incidentally, has an in-house mould-making unit, the moulds from which are employed not just for its own plastics production, but also sold in the market to other plastics producers. Early this year, TPSL managed to bring down its production time considerably, while cutting down the cost by 30 percent.
This tallies with Alcan’s (the leading aluminium producer in the world) economic analysis of the mould construction and utilisation phases, for aluminium (the Certal brand) and steel (Ck45 steel). Aluminium is costlier than steel by approximately 60 percent, but the machining and energy costs are less than half of those for steel. This more than offsets the extra costs incurred while purchasing the material. For a given weight of material, for every steel mould, 2-3
similar aluminium moulds can be made.

Tool Concepts For Die & Mould
HITACHI is one company that has been focusing developing new tool geometries, inserts and cutting tool materials for high performance cutting (HPC) of dies and moulds. These developments aim to improve performance, productivity and profitability. The introduction of the tools for very high feed, plungers for high productivity in machining deep cavities, and
drills for high efficiency in drilling are some examples.
Optimisation of the insert and chipformer geometry in milling, drilling, and profiling improves accuracy of the machined surface, provides more tool life, reduces cutting forces and vibration and makes fast metal removal (FMR) possible. For roughing applications on dies and moulds, new tooling technologies such as plunging tools, ramp-down tools or milling cutters with helical cutting edge inserts like are used.

• Helical Inserts

ATC and ATB from Hitachi Tool
Helical inserts have been developed for shouldering, facing, slotting and profiling This type of tool solves the main
geometrical disadvantages which are the lack of workpiece side wall straightness, flatness, and perpendicularity of a
straight cutting edge insert positioned with a positive axial angle. Inserts are made of submicron substrate with improved toughness and hardness, better resistance to chipping, and high wear resistance.
The TiCN coated tools are recommended for most of the standard applications in machining alloy steel and tool steel materials. The TiAlN coated tool is an excellent grade for hard machining, dry cutting, and on high-temp alloys. The machining of dies and moulds made of alloy-steel in the soft and hardened state with the new PVD-TiAlN coated tools improves tool life significantly.

• Facing With Very High Feed

ASR Type EndMill can withstand the maximum 20m/min or more, cutting feed rate of the latest machining equipment. Compare with Bull Mill from Taegutec is not efficient for Indonesian workshop because need high tech machine and price too expensive.
For facing with very high feed rates HITACHI has developed a special super radius-shaped positive insert having a cutting-edge configuration with a very large radius. In this unique FEEDMILL geometry the relative small insert design with positive rake angles is recommended for small depth of cuts and very high feeds providing easy chip flow, lower cutting forces and a stable operation. The tools can be used for fast metal removal in machining dies and moulds with deep cavities with large overhangs at very high feeds, up to 3.5 mm per tooth.

• Profile Shaping With Very High Feed

ETM EndMill is the best endmill i ever use.

Moves In Machining
Just as one material has replaced another in moulds for certain applications, there are numerous instances of one machining process being replaced by another, superior to the former in certain respects. One such is trochoidal milling, which has proved to be a more efficient and quicker (by some 30 percent) method of machining fillets, pockets, slots and grooves in moulds, as compared to conventional milling.

In conventional milling, the cutting tool moves along straight-line paths, and the machining of a curved contour, involves the formation of a series of steps at right angles to each other, which are then progressively flattened out to form a continuous curve. This calls for a series of finishing operations. Besides, manual polishing is required as a final step to even out the inevitable aberrations.

In trochoidal milling, however, the cutting tool moves about along a curved path, which in geometry could be termed as a ‘trochoid’ ie: the curve traced by a point within a rolling circle, which is not its centre, between the end-points specified in the CNC program. The ‘step formation’ typical of the conventional milling method, is not characteristic of trochoidal milling,
and manual polishing which accounts for a significant portion of machining time in conventional milling, is almost entirely dispensable.

Software Solutions
Software is now a major component in the mould and die process. There are many CAD/CAM software suppliers in the market today, distinguished from one another by the features they provide, as well as by the nature of the after-sales service that is extended to the clients in the global market.
Vero International, NC Graphics and Delcam all have a strong presence in the die/mould sector; in fact, a majority of their clients belongs to this sector. Vero International Software’s VISI-series CAD/CAM software has recently been upgraded to include applications for 3D component design, plastic mould tool design, sheet metal tool design, progressive die design, 2D CAM, 3D CAM, continuous 5-axis machining, wire EDM and high speed milling. The 5-axis machining module enables the spindle (and a short tool) to be inclined to reach otherwise inaccessible nooks and crannies inside the mould – deep cavities and small radii. This spindle-adjustability obviates the need for tool extensions or longer tools, which would involve problems of deflection and poor surface finish.

The Message: Get Integrated
Early this year, a pan-European team working on a two-year, EU-sponsored project, emould@work, which attempted to find out what ailed the die/mould makers in the EU, published its findings, after studying the operations at several units.
Stuart Watson of Delcam, the Project Leader summarised the findings of the team for MEN:

• Communication/collaboration problems: Almost half the lead-time for a mould is spent on waiting for data, changing poor data, discussing such changes, etc. Basically, integration between the design stage and the machining/assembly stage leaves a lot to be desired.

• Poor process flow: Nearly 50 percent of the mould makers around the world are working in two parallel streams with the core/cavity done using a 3D surface modeller and the mould assembly done in 2D using a 2D drafting system. The others have replaced 2D drafting by solid modelling, but still have two departments because the solid modeller in vogue cannot do the core/cavity work, while surface modeller cannot accomplish the solid assembly modeling. This, inevitably,
creates a lot of idle time.

In a nutshell, it is not enough if the mould machining department is well equipped with the best CNC machines and highspeed
cutting tools. The design stage has to be seamlessly integrated into the manufacturing stage.
The suggestions of the emould@work project team can be extended to the other parts of the world. If there is a difference, it would just be a matter of degree.