Conveyor technology in clean rooms

In a cleanroom environment, factors such as ease of cleaning play a major role. Standard motors with their cooling fins and associated small recesses are often counterproductive in this respect. Environmental dust collects here and is difficult to remove.

Most motors also have fans to cool the motor. In some applications, however, this can disrupt the laminar air flow and cause unwanted turbulence in the ambient air.

MTF Technik offers smooth-shell motors for these applications. These have smooth outer surfaces and are therefore easier to clean. In the hollow shaft motor version, it can be mounted directly onto the drive shaft. This eliminates the need for a chain drive and the associated lubrication work.

Even more elegant is the integration of the motor and gearbox into the drive roller. This is usually recommended by MTF Technik for conveyor belt drives in clean room conditions. The main advantage is that virtually nothing of the actual drive is visible. Only the motor cable outlet is led out of the conveyor belt body.

This means there are even fewer protruding parts and the smooth surfaces of the guide profile can be cleaned quickly and easily if necessary. Here, too, there are no air turbulence caused by the cooling of the motor, as it dissipates its heat via the belt.

To prevent components from becoming contaminated by environmental influences during transport, conveyor belts are often equipped with covers. These can be made from various materials, such as aluminium, stainless steel, PET, Macrolon, etc., and in various designs, such as plug-in, foldable, fixed, with handle, without handle, etc.

Functional aspects play a role in determining the exact design. For example, collision points with existing interfering contours due to machine geometries must be taken into account, as must the behaviour of the conveyed material. For example, can products accumulate during the conveying process and become jammed under a cover, etc.?

Various factors must be considered when selecting materials. For example, the ability to monitor the process naturally favours transparent covers, but depending on the material, these can become "blind" over time, e.g. due to cleaning or contact with the conveyed material, or attract dust.
In addition, there is often a requirement that components manufactured outside the actual cleanroom using a filter module on the production machine must be transported into the cleanroom via enclosed conveyor lines.

For this purpose, the profiles of MTF Technik conveyor belts can be completely closed at the belt inlet. Covers above and below allow a completely encapsulated conveyor line to be realised. This saves valuable cleanroom space and thus significantly reduces costs.

Encapsulated transport routes in buffer systems can also be implemented in this way.

There are various methods for ensuring that a flexible plastic belt runs straight on a conveyor belt. MTF Technik has always preferred belt centring using conically turned drive and deflection rollers. The conicity of the rollers achieves a certain self-centring effect of the belt – the belt tends to run to the highest point, i.e. to the centre of the belt.

In contrast to positive guides, such as guide strips or profiles attached directly to the side of the belt or so-called wedge guides, the conical rollers guide the belt without any contact between the moving belt and the fixed frame.

The belt can run freely and is adjusted so that it has sufficient space on each side. This consistently prevents abrasion.

In clean rooms, it is extremely important that all surfaces are designed to be as easy to clean as possible and that all areas are as accessible as possible. MTF Technik offers aluminium profiles with anodised surfaces that feature a high level of expertise in the details. For example, the side sealing strips are attached to the actual guide profile using a clip mechanism.

This allows us to easily adapt to different running deck thicknesses and make the gap between the fixed profile and the moving belt as large as possible or as small as necessary. In clean room applications, we try to achieve the largest possible gap between the belt and the side guide or sealing strip to prevent contact and thus abrasion. However, the extent to which this is possible also depends on the conveyed material, as no components must be allowed to slide into the gap.

The clip mechanism means that no screws are required for fastening in the area that comes into contact with the product. This results in completely smooth surfaces that are easy to clean. The absence of screws also prevents the formation of impact edges that could damage components.

The sealing strips are also slightly bevelled at an angle of approximately 6°, creating an upward-opening geometry between the drive lugs and the sealing strip. This prevents components from jamming or rubbing in this area.

Static charges on components occur repeatedly, especially in the manufacture of plastic parts. In addition to the potential risk of electric shock to employees, these charges have the negative side effect of attracting dust, especially in clean rooms.

To prevent this, the components must be discharged. MTF Technik uses different ionisation devices from various manufacturers depending on the application. The devices are then usually mounted on belt covers or transfer hoods to supply the conveyed material with ionised air as required.

Further details on this topic can also be found in our on the subject of "Static charge".

Further practical application examples on the subject of clean rooms can also be found under our industry solutions