CAD/CAM Optimizes the Production of Small, Complex Molds from Design to Delivery

Mecca T.P., an Italian moldmaker producing tools for thermoplastic materials and die-castings, serves a variety of industry sectors, including medical, automotive, household appliances, furniture and eyewear. Founded in 1985, the company is run jointly by Antonio Tognon and Renato Prosdocimo, based in a 2,000-square meter production unit in Bigolino di Valdobbiadene, Treviso, Italy, with an annual turnover of around 1.5 million euros. The company produces between 40 and 80 molds a year, ranging in size from 200 mm x 200 mm x 200 mm to 600 mm x 800 mm x 700 mm.

Antonio Tognon says their molds have to be produced swiftly and accurately, first time every time, without the need for changing them unless requested by the customer. “And in those cases, the changes have to be carried out quickly.

“Over the years we’ve developed our production process in order to minimize manual intervention on the molds, controlling the machining operations,” Tognon says. The company has always adopted the most advanced technologies, from two and four-axis wire EDM, to high-speed three and five-axis milling, along with their CAD/CAM VISI software which is proving to be a vital aspect in ensuring that the molds are consistently manufactured to the high precision required, from the design process through to the final mold.

The company uses VISI Mold by Hexagon for the design, while electrodes are modeled and machined with VISI Machining 3D, which is also used for cutting plates and molding parts, along with Machining Strategist and VISI Wire. To import, prepare and validate imported data, VISI Analysis finds potential problems at an early stage, generating huge time savings further along the design process.

“Being able to identify complex mathematics in advance lets us discover critical areas at an early stage of the project and greatly simplified our work. It also leads to a significant reduction in both design and production times.” 

VISI is used in the preliminary stage, before the design process begins, to analyze details such as drafts, undercuts and thicknesses, and to draw up possible dimensions of the finished molds. “We import customer STEP, IGES or Parasolid files and analyze the geometry in depth, to define the quality of the mathematical model, while correcting incomplete or inaccurate geometries.”

According to Tognon, the software gives them the capability of managing and graphically displaying mold creation and any required changes in real time. VISI Mold guides the user through the mold development process. The team follows the proposed mold design, adopting various solutions for mold movements, conditioning circuits, injection and extraction systems. They then move on to create the mold basement and define details, before sending the component parts to the different CAM stations for milling, wire cutting, and electrode modeling and construction.     

Tognon cites an example of a stainless steel mold that Mecca TP has developed to replace an existing mold used by a client in the medical sector. The mold was to produce a small circular component with a diameter of approximately 40 mm. The part had to be molded in a white chamber on eight impressions, in a complete discharge cycle of less than 20 seconds. It featured complex, irregular surfaces and a different front and back finish, and a shiny, mirrored surface on one side. He says the main challenge was to find a way to free undercuts; also, to create the movements necessary to obtain a high-quality piece – molded from soft adhesive PVC – in the correct way, avoiding possible wastage.

“We created a completely new movement, very different from the mold originally being used by the customer,” Tognon says. “Our proposal optimized the intrinsic characteristics of the impressions, and the operational flexibility, ensuring the highest level of productivity. Each imprint has a completely interchangeable matrix and punch, which are fixed to the mold by screws. This means we can replace them when they are worn out, without changing the entire mold, even if the mold is inside the machine. It also means we can produce different products using the same mold.”

In conclusion, Tognon says VISI optimizes their entire process from design to delivery, and means they can comply with increasingly tight delivery times. “We see very complex molds every day. Calling them ‘molds’ is almost reductive. I’d rather define them as ‘advanced equipment.”