Rubber world

The world of molded rubber parts.

The world of molded rubber parts.

Important terms relating to the production of molded rubber parts are briefly explained on this page.

First falling molded rubber parts, which after the sampling process are released by the customer for series production if they are free of defects.

At Knorr & Macho GmbH the molded rubber parts are delivered according to the following delivery methods: on call, according to Kanban, or just-in-time. Which delivery variant you ever prefer, you are always guaranteed flexibility. Short-term changes in delivery times are also not a problem for us.

Are polymers made up of macromolecules, which are cross-linked in a three-dimensional, wide-meshed manner. This cross-linking of the individual polymer chains (vulcanization) leads to the rubber-elastic properties of these materials. In common parlance, elastomers are therefore also referred to as rubber.

The excess mold burr or the attached waste of the rubber molded part is removed. This can either be done by tearing off and cutting by hand, or in the form of mechanical deburring.

In this process the respective molded rubber parts are deburred with liquid nitrogen in connection with granules, or the remaining protruding rubber is removed. This gives the molded rubber part its final desired installation shape. Depending on the molded rubber part, exact setting parameters are defined and documented. This process ensures a permanent, even and clean finish at all times. A color change of transparent and colored molded parts does not occur 100 percent. We can carry out cold jet deburring between -20°C and -120°C.

In this process the respective molded rubber parts are deburred in liquid nitrogen without being connected to granules, or the remaining protruding rubber is removed.

Are often confused with the failure pattern. Initial samples are molded rubber parts manufactured under series conditions (standard equipment and conditions). These are checked for compliance based on the customer's specifications for the respective molded rubber part, such as: dimensions, material properties, functionality, and if the result is positive, the customer releases them for series production.

The initial sample test checks the specifications specified by the customer according to the following criteria, for example: dimensions, material properties, functionality and other requirements. The customer's specifications and the results obtained are then compiled in an initial sample test report. This contains all TARGET and ACTUAL values ​​of the characteristics to be checked. The initial sample test report consists of a cover sheet in the sense of specified target values ​​and the test results based on these in the sense of actual values ​​acquired.

Results from the performance, respectively the injection cycle per hour x number caliber / nestsof within the tool design.

Total amount of possible molded rubber parts to be manufactured in one year. Calculation: possible production hours / day x working days per month x working months per year.

Adhesion agents are polar dispersions of polymers, pigments and crosslinkers. A distinction is made between solvent-based and aqueous adhesion promoters. And between one-component and two-component adhesive systems. In the case of two-component adhesive systems, a so-called primer is first applied to the pre-treated metal surface. After the primer has dried, the actual adhesion agent is applied.

In the injection molding process for the production of molded rubber parts, the rubber mixture is first preheated and plasticized (80-100°C) in an injection molding machine in a screw unit and then injected into the heated mold via sprues. Depending on the design, a distinction is made between horizontal and vertical injection molding machines. The injection process takes place either by moving the screw directly in the cylinder or by injecting via a separate cylinder (injection piston). Compared to the compression molding or pressing process (CM), the IM process is the more modern manufacturing process for molded rubber parts. Due to the plasticization in the injection unit, significantly shorter heating times can be achieved compared to the CM process. If suitable handling technology is used to remove the molded rubber parts, a fully automatic molding process is also possible. The elastomer material that vulcanizes in the runners must be disposed of as vulcanization waste. However, this amount of waste can be significantly reduced by using nozzle cold runners.

Number of rubber molded parts which are designed in a respective injection molding tool. Tools with a variety of caliber / nests, however, are not always synonymous with a more cost-effective production method.

Low-temperature sprue area of ​​a mold in which vulcanization of the elastomer mixture inside is prevented. With a cold runner the amount of vulcanized waste produced during the production of molded rubber parts can be significantly reduced, since the unvulcanized material in the ducts can be used to produce molded parts. Depending on the design, a distinction is made between nozzle cold runners and transfer molding cold runners.

After completion of the tool, the initial sampling and subsequent series production take place immediately. We therefore always guarantee you the fastest possible delivery (approx. 1 - 2 days, depending on the process).

Depends on tool design and degree of difficulty. However, as your tool specialist, we can usually give you the following times. Sample form usually 2 weeks. Serial form usually 4-5 weeks.
"Short-term Tool for the relocation of the Knorr & Macho GmbH, as quickly as possible, a conceptual tool change and subsequent production in a few days, are also part of our portfolio, and is a further strength of us".

1-2 caliber tool for the first test run of the manufactured molded rubber part. Advantage: gaining experience in relation to the subsequent use in series, lower cost risk in relation to series processing, short delivery/procurement times.

Manufactured pattern moldings from the pattern mold.

Molded rubber parts after approval of the initial and outturn sample.

Shore hardness is the resistance of a rubber sample to penetration by a cone-shaped body of certain dimensions under a defined compressive force. Depending on the design of the measuring body, a distinction is made between Shore A for softer elastomer mixtures and Shore D for harder elastomer mixtures.
For the proper measurement of Shore a hardness is required by the standard, a sample thickness of 6 mm. Measurements of finished parts with a lower wall thickness usually lead to incorrect results.
Common Elastomer compounds for technical molded parts are in a hardness range of 20-90 Shore A.
In addition to Shore-a hardness test with a cone-shaped test specimens, there is the IRHD hardness according to DIN ISO 48, with ball-shaped measuring bodies.

Always depends on the following processes: Injection of the elastomer, vulcanization process, mold opening, demolding process of the molded rubber part. These processes times the number of subsequent processes within an hour then results in the injection molding cycle, or injection molding cycle per hour.

Usually according to DIN 3302-1 -M3 or by arrangement for individual items.

This process hardens molded rubber parts that have a mold structure that is still too soft. This gives the molded part its actual degree of hardness for the required area of ​​application. Likewise, the chemical substances contained in the molded part (e.g. plasticizers, vapors, etc.) that could have an impact on its functionality are removed.

The material to be processed is the elastomer (plastic or rubber). Different elastomers are used depending on the legislative guidelines, injection molding process, areas of application of the molded rubber part and customer requirements, especially in the automotive industry.

Design or construction of the tool based on the molded rubber parts to be manufactured. Only an optimal design i.S. the way it works guarantees 100 percent molded part quality and cost-effectiveness. The Knorr & Macho GmbH specializes in this area and has been working successfully with experienced and very flexible toolmaking companies for many years.

After sending a transfer document we will store your tools professionally with us if they are not in production. All tools are insured for the time they are provided.

The costs of the respective tool are always dependent on the tool design and its specification. Speak in terms of the size of the rubber molded parts and their geometry.

The tool life cycle describes the lifetime of a tool. This always depends on the elastomer used, the respective tool design, as well as tool maintenance and care. All tools manufactured by Knorr und Macho GmbH are defined before the actual series production based on a tool life cycle and contractually recorded with the customer.

Vulcanization is the chemical-physical transformation in which the predominantly plastic caoutchouc changes into the rubber-elastic state. This process, which takes place by linking macromolecules at their reactive sites, is also called crosslinking. A vulcanizing agent is required for vulcanization. The oldest and most common vulcanizing agent (crosslinking agent) is sulphur.