The injection molding experts at CAVITÄT in the German community of Hörden greatly appreciate the benefits of HASCO’s two-stage ejectors. The two-step distribution of force of the two-stage ejectors enables the demolding of complex parts at high demolding temperatures – without any warpage or deformation and without any marks left behind by the ejector. The energy consumption for cooling can be reduced and the cycle time can be shortened.
The performance promise given by CAVITÄT GmbH is to ensure fast product development at consistently high quality level within the entire production process, from the initial design of the component, through mold development to final production by injection molding. Orders come in from a wide variety of different industries, predominantly (70 %) from the automotive segment but also from the fields of consumer goods, medical technology, protection technology, the electrical industry, automation and handling technology.
Economical production is of major importance for CAVITÄT. The moldmaking operation, which originated many years ago from a construction bureau, is equipped with state-of-the art automated machinery. Three HSC machining centers are in operation, two of which are integrated into a handling system and, under optimum circumstances, run 24/7. Even the erosion sector is fully automated.
“Formerly, our focus in the automotive segment was clearly on visible components,” says Jörg Kroß, CEO at CAVITÄT. “However, for some years now we have been manufacturing mainly molds for technical components in this sector.” The chief requirements apart from high dimensional stability, excellent surface properties and other quality criteria are above all short cycle times with good ventilation and low warpage. The molds are designed sustainably for high, reliable quality and optimum economic efficiency in production.
In moldmaking, standards are deployed to ensure both quality and economic efficiency. Alongside our high-quality in-house production, we also rely on standard parts and components from well-known manufacturers,” explains Kroß. “Since our company was founded nearly 20 years ago, HASCO has been our cooperation partner. We purchase virtually all our plate material from them, but also numerous accessory components.”
In a current project – a molding tool that was designed for the production of a plastic hose holder for the automotive industry – CAVITÄT used a two-stage ejector from HASCO. This is a thin-walled cylindrical injectionmoulded part with details for fixing in the vehicle.
“With this mold, the challenge was not the free movement of the injection molded component but the specified narrow tolerances for the diameter, which did not allow any demoulding-friendly modifications to the design of the product. The mold had to get by in this area virtually without any draft,” says Kroß. “Here, we used a different property of the two-stage ejector: A constant ejector motion was transferred to a controlled two-step distribution of force. This enabled demolding forces to be reduced and allowed much earlier demolding.”
The mold experts at CAVITÄT put a relatively large amount of energy, work and time into the projects at a very early stage during the design of a mold in order to be able to build an optimum product. Filling analyses and simulations help to save correction loops. The idea is that the articles exit the mould in perfect shape – if possible, immediately after the first trial.
“Our client produces his articles on all-electric machines and he wants to make full use of the speed of the machines,” says Kroß. “This means that we must design our mold for a cycle time that is as short as possible so that he can fully exploit the potential of the processes.” Apart from a well thought-out cooling concept, this also involves demulding the article while still “hot” with as short a cooling time as possible. Here, too, the challenge is to exploit the process to the limit, without impairing process reliability or process stability. This means that the article is relatively soft when demolded. Conventional ejectors leave undesirable marks behind when ejecting at high temperatures.
elevated temperatures. Photo courtesy of CAVITÄT
The HASCO two-stage ejectors offer the optimum solution for a reliable and controlled process. With a comprehensive range of two-stage ejectors, HASCO offers numerous customized possibilities for reliable movement control and demolding during the injection molding process. The various designs and dimensions can be used as upstream or downstream leading systems. All two-stage ejectors are available ex stock with DLC coated functional surfaces. This enables operation of the injection molding tools with very little wear and tear. Maintenance intervals can be extended and wear parts can be replaced very much later.
“The possibility of reliably demolding the article while still in a fairly warm state, shortens the cycle significantly,” says Kroß, summing up. “We were able to reduce the time taken by 20 % from around 25 sec to 20 sec. This is pure money for our client – he can supply his customers faster and has the injection moulding machine free much more quickly for the next order.” In addition to this, the solution offers a high level of process reliability.
One very positive aspect for CAVITÄTis that individual parts of the two-stage ejectors can be ordered very rapidly and easily via the HASCO Portal, and reliable delivery ex stock is guaranteed. “This gives our customers additional certainty of being able to continue working quickly and uncomplicated in the event of a repair, something which is a very important argument in view of the ever tighter deadlines,” says CEO Kroß.
The close partnership between CAVITÄT and HASCO and the shared practical know-how of the experts among one another enable competitive and highly productive solutions – to the benefit of the customers.
As published in The mold & die journal 06/2022”
