Customised parts holders The perfect parts handling solution

Safety is the top priority when cleaning components of medical devices. Individually designed parts holders offer the best possible protection for the components during the cleaning process and make parts handling easy, as the following practical example shows.

Fortuna GmbH, a company based in south-west Germany, manufactures splitting and skiving machines used in the industrial processing of leather, plastic, rubber and technical textiles throughout the world.

The company was recently presented with the new challenge of developing a splitting machine for highly sensitive medical products used in operating theatres. "The aim was to automate a process that had previously been carried out manually with a scalpel and therefore to improve the quality of the results. Alongside high levels of precision when splitting the product and re-sharpening the knife, we had to be able to guarantee that batch A of the product would not come into contact with batch B during processing," explains Hans Laßnig, project design engineer at Fortuna.
In order to prevent this type of contamination, all the components of the machine that could possibly touch the product have to be removed and cleaned after every splitting process. The customer specified that the time needed to refit the machine and clean the components must not exceed 30 minutes. "We had to design the components in such a way that they could be removed and replaced quickly and still meet extremely tight tolerances. We also needed parts holders for the cleaning and sterilising process that the employees could quickly put the components in immediately after removing them, without mixing them up," said Laßnig.

Overcoming the challenges
Being able to put the parts in the holders quickly and without them becoming mixed up was only one of the requirements. In addition, the holders were required to hold the components securely in place with the minimum of contact, taking into account that some surfaces must not be touched at all. The components should not touch one another or the metal surface of the parts holder during the cleaning process.

Furthermore, the machine components had to be positioned in such a way that undercuts and blind holes could be cleaned reliably, but that neither the cleaning fluid nor condensation from the sterilisation process was allowed to collect in them, as this could have been carried over to the machine. A further specification was that the baskets must not weigh more than 20 kg, because this would have required additional handling equipment. The baskets also had to be stackable.

At an early stage of the project, Fortuna identified Metallform as the ideal supplier to solve these problems. The detailed requirements were defined in the company's headquarters in the German town of Bretten using 3D data. Some of the issues which had to be resolved included how the parts should be held in place so that the liquid ran out, how the parts could be dried effectively and how to ensure that no cleaning fluid or condensation was carried over into the machine.

Holders for each specific part in standard baskets
The solution consisted of three holders designed specifically to accommodate the different parts. The design is such that only one specific component of the machine will fit in each type of holder. One of the holders is fitted with a basket to take small parts such as screws and threaded studs.
Particular attention was paid to the contact surfaces. The aim was to ensure that the contact points between the parts and the holders were as few and as small as possible. This is because each contact point brings with it the risk of contamination or cleaning agent adhering to the parts or of the parts not being fully cleaned or dried in these areas.

Direct metal-to-metal contact was avoided by covering the contact points with Teflon clips. In comparison with a coating, this solution has the advantage that the clips can be replaced quickly.
In order to meet the requirement for stackability and ease of transport, the parts holders were fitted into two MEFO-BOX containers 480 x 320 x 200 mm (length x width x height) in size and one 480 x 320 x 108 mm in size. The 16 mm high stacking frame on the baskets allows three to be stacked together safely and easily to make a batch, so that the complete set of parts is ready for installation in the splitting machine after cleaning and sterilising. Both the parts holders and the containers are made of stainless steel rods with an electrolytic polished surface. The high quality material, which has a long service life, will prevent the components from being contaminated by the parts holders and the baths from being contaminated by corrosion and zinc deposition.

All the joints between the rods are fully welded, which means that there are no sharp corners, edges or pieces of wire which could injure the employees as they insert the components.