There is, of course, more than one way to answer the machining challenges, so it's no suprise that multiple solutions grow out of the ingenuity of both Moldmakers and Machine Builders. Two of the solutions are found in readily available, large capacity Machining Centers, and in newly available, larger size EDM Machines.

Why Larger Parts?

The parts that are driving the trend toward larger Moldmaking capacities are used in a greater number of diverse manufacturing industries. In spite of the broad variety of part design, they all share several similarities, besides the escalation of part sizes. These similarities are:

Economy of Design

There is a popular ongoing trend to combine parts. The resulting combination eliminates assembly operations, thus reducing costs. However, this results in still larger parts.

Plastic vs. Heavier Materials
(metal, wood, masonry, etc.)

Moldmaking in general has benefited from the persistent trend to eliminate heavier parts. Not just to lower the weight of the finished product, as with the Automotive industries -- but to control the difficulty in part handling and assembly, where weight directly effects manufacturing costs. Lowering shipping costs are also a prime reason to reduce the weight of large manufactured parts.

Reinforcing Ribs

There has never been a better time for aesthetics. Designers are having a heyday with sweeping curves, bending contours, and pleasing lines. Yet one fundamental equalizer is that part strength, in every industry, is a requirement. The design feature that provides the necessary part strength, without adding to the bulk, is reinforcing ribs. Thus, the machining problem when building the molds is two-fold -- the depth of the ribs, and also their position -- since the rib's location can occur at any number of angular positions.

The rib factor in Moldmaking has always been a challenge, often with requirements to create ribs that are many times deeper than their width. The EDM Machines that are capable must possess rigid yet sensitive motion control, and also angular positioning capability to accurately position the rib.

Large Multi-axes Machining Centers

Some Moldmakers take the "chip making" route and contour-machine their large molds via CAD/CAM and Multi-axes Machining Centers. Equipped with a swivel head, and working in tandem with the existing axis, most contours can be machined effectively. The cost however, of this type of machine is quite high -- usually several times what a larger Sinker EDM costs. And still, complicated details along with ribs require EDMing. However, the EDM Machine capable of completing the machined cavity must be able to first accept the mold block in both size and weight, and provide access to all areas of it. It should be capable of indexing and swiveling.

Large Multi-axes Sinker EDM Machines

As the size of the EDM Machine grows, design considerations also grow. Rigidity is a major factor, as is the sizing of servo components to assure the same reliable motion that is so vital to precision EDMing.

The need for large plastic parts did not occur overnight. As with any major change in manufacturing, it happens in a slow steady manner. Moldmakers are starting to find out that their EDM machines are too small, however they, and their bank account, may not be ready for an enormous EDM Sinker just yet -- when a somewhat larger one will do for a period of time.

There is a temptation, however, to acquire an EDM Machine with just a larger tank size and not consider the X-Y travel necessary to access all areas of the mold block that fits into the tank. A conservative approach to the problems spawned by the escalation in mold sizes, has recently been taken by an EDM Machine manufacturer, aptly named EDM Solutions.

The EDM Solutions Approach

Although their approach is conservative, it is also functional. First, the machine must be entirely capable of supporting greater weights without distortion. Their major conceptual difference is that, for every inch of increased part size capacity, an equal inch of X-Y motion must be provided, so that the word "capacity" has real meaning to the Moldmaker.

According to EDM Solutions, the result of their functional approach is contained in their new FOX series of machines. These larger machines feature X-Y motions (real capacities) of from 40" x 80", up to 80" x 160", in 6 different machine models.

Other specifications include head weight capacity of 2,200 pounds, and a table weight capacity of 45,000 pounds. The customer can specify the work tank size, machine stroke, and open height (daylight).

EDM Power Considerations

A key issue at EDM Solutions is the focus on power. They feel that high metal removal rates and minimum electrode wear should be available at all settings, including finishing. The higher the Amperage available, the faster you remove metal, and the more productive and profitable the EDM operation will be.

As a result, they provide a full 300 Amp power supply with the FOX Machine Series. Given the power capabilities, the full capacity motion, and standard C-axis provided with the machines, EDM Solutions expects many of their customers will choose to equip their machines with a second head. A tandem head is an efficient method of sinking in two locations in one part, and performing multiple part EDM machining, similar to the operation of a CNC multiple head milling machine.

EDM Solutions -- The Company

The Management likes to refer to EDM Solutions as the "oldest new company in EDM." This is partly because they are an outgrowth of their parent firm, SK Enterprises, which for over 25 years has been one of the major EDM marketing firms in the Chicago area. The other reason is because of the key-people experience in Sinker EDM applications, the sum of which adds up to decades. More importantly however, is the fact that the investment in software and hardware development by SK continues under the EDM Solutions banner.

According to EDM Solutions, support for their customers includes hands-on training and applications orientated training manuals, of which the firm is very proud. Individual applications assistance, for customers with complex and multiple parts, is a way of life for the EDM Solutions staff. They like to say that they provide the EDM Solutions to EDM problems.