Cleaning effort – a question of the right basket

Damit das Reinigungsmedium und die Mechanik ihre Wirkung voll entfalten können, ist eine gute und allseitige Zugänglichkeit zum Bauteil unverzichtbar. (Abbildung: Metallform Wächter) / Good parts accessibility is achieved by the use of rounds and the avoidance of closed corners and edges. The open design also allows that the particles can be washed out of the basket quickly and effectively. (Image source: Metallform Wächter)

In Reinigungsbehältnissen aus Rundstäben sind die Teile von allen Seiten gut zugänglich. Die offene Gestaltung trägt zu einem effektiven Schmutzaustrag sowie zu einer schnellen Trocknung und minimierten Verschleppung bei. (Abbildung: Metallform Wächter) / Flexible solutions with parts specific inserts – here with damage prevention made of Teflon lagging – and multi-purpose outside racks, achieve significant cost reduction for the investment in cleaning baskets. (Image source: Metallform Wächter)

Flexible Lösungen aus teilespezifisch gestalteten Einsätzen – hier mit Bauteilschutz aus Teflon-Ummantelungen – und universell einsetzbaren Außengestellen, ermöglichen eine deutliche Kostenreduzierung bei der Investition in Werkstückträger. (Abbildung: Metallform Wächter) / Cleaning medium and the mechanics can only exert their effect when the parts can be reached freely. (Image source: Metallform Wächter)

Durch so genannte Umstülplösungen lassen sich erforderliche Umsetzvorgänge der Teile optimal gestalten. Die sehr hohen Kosten für das manuelle Umsetzen und das Risiko einer Bauteilbeschädigung werden minimiert. (Abbildung: Metallform Wächter) / Transfer operations can be configured in an optimal way with inversion solutions. High costs caused by manual transfer and the risk of parts damage can be reduced. (Image source: Metallform Wächter)

Whether 1000 microns, 800 microns, 600 microns or less – to meet defined particulate cleanliness requirements in a reliable and economical way, poses a challenge for many parts manufacturers. The cleaning baskets are one aspect that is often forgotten or considered too late when cleaning processes are planned. Although the cleaning baskets and workpiece holders have essential effects on quality, effort and costs of the parts cleaning as well as on handling and logistic processes.

The demand for a high throughput while maintaining defined cleanliness requirements can only be met with an optimal adapted cleaning process.
The key factors here include the chemistry, temperature, processing time and mechanics like ultrasonic sound, spraying and injection flood washing.

From efficiency point a process is optimal, when the use of chemicals, temperature and time can be reduced to a minimum – thus the required result can be reached with high throughput within short time and at the lowest possible costs.

This requires that the effect of the mechanical processes arrives to virtually 100 percent at the parts that have to be cleaned and that the potential of the machine can be fully used.

Now the cleaning basket comes in. It decisively affects not only the quality, time and costs of cleaning but also affects the parts handling for upstream and downstream production steps, the logistics as well as the process automation.

Basic requirement – good parts accessibility

Regardless of whether parts are cleaned in bulk or set goods, both the cleaning medium and the mechanics can only exert their effect when the parts can be reached freely. Therefore a good all-round accessibility is a basic requirement that a cleaning basket has to meet. This is achieved by the use of rounds and the avoidance of closed corners and edges. The open design also allows that the particles can be washed out of the basket quickly and effectively and can be lead back to the filtration. When drying by hot air, the required time is significantly reduced due to the good accessibility of the parts. When it is about the bath life time, the all-round accessibility also offers non-cash benefits, because it reduces the carryover of cleaning media. This leads to higher bath changing intervals and therefore a higher availability of the machine.

Efficient cleaning baskets  – an interaction of lots of factors

To adapt the cleaning basket to the process and the cleanliness requirements at its best, moreover different parts and system-dependent information have to be considered. According to Metallform the relevant component factors are the geometry of the parts and the material from which they are made. The question of critical areas on the parts also plays an important role. Moreover the quantity of workpieces, that have to be placed in a workpiece holder as well as any existing parts families like box-shaped or cylindrical workpieces are incorporated in the design process. Important information regarding the cleaning machine are the batch size, the supply and the fixing of the batch in the working chamber, the goods movement during the process and the used media. For optimal integration of the cleaning baskets in the individual operational processes, information about the processes upstream and downstream to the cleaning, the therefore necessary parts handling and already existing cleaning baskets are required. It is also helpful for the manufacturer of cleaning baskets to know in which industry a company is working.

Based on this information, Metallform designs cleaning baskets with the latest CAD technology, which redound to a reliable, cost-efficient and resource efficient parts cleaning. This includes for example the optimal positioning of the parts in the workpiece holder. This allows a selective treatment of for example bore holes and undercuts without affecting on the sensitive areas. In doing so the adjustment to the parts movement, for example lifting or rotation, ensures that the parts are securely held and aren’t damaged.

The minimised contact area between the part and basket which is achieved by the use of rounds, reduces the risk that particles or cleaning media stick to the parts respectively that the workpieces don’t dry completely on the contact areas and get spots. Coslty reworks and expensive rejects can be minimised.

Flexibility thinking ahead

A criterion that also runs into the design is the variety of the parts that have to be cleaned respectively a quickly changing range of parts. For those applications Metallform develops flexible solutions which achieve significant cost reduction for the investment in cleaning baskets and still high process reliability. They are composed of parts specific inserts and multi-purpose outside racks and adjustable lids.

Integration in the internal processes

When it’s about efficient processes, also the costs for internal and external transports as well as the required parts handling have to be considered. The trend today is to use cleaning baskets also for different transport tasks. In this way unnecessary work and allocation of personnel, costs for the cleaning of storage and transport boxes as well as the contamination or damage of parts while transferring them can be avoided.

The hereby relevant factors are also included in the design. At the same time the coordination between all baskets that are used in the production, for example for the manufacturing, cleaning, transport to subsequent processes, logistics and assembly allows that transfer operations between the individual production steps can be reduced. Transfer operations that can’t be eliminated, can be configured in an optimal way with inversion solutions which are exactly adapted to the individual task.

The automatic loading and unloading of workpiece holders requires an extremely high level of accuracy in the dimensions and position of the parts in the basket. This often seems to be practicable only with a closed structure of the workpiece holder, which however has a counterproductive effect on the cleanability of the parts. At this point solutions especially designed for cleaning enable an improved cleaning quality and a higher throughput.

Selection of material and workmanship

The material that is used for the cleaning baskets must not affect the cleaning. With a water based cleaning agent for example, metallic protective coatings can be detached from the basket and can lead to an impairment of the cleaning result and cause problems with the wastewater treatment. A material that is suitable for all cleaning media is stainless steel. Furthermore the cleaning baskets should not have any sharp edges or loose wire ends, by which employees can be injured.
An exact consideration of the cleaning basket pays off, as it contains a great potential to make cleaning processes more reliable and efficient.