Getting the best from your steel bake oven belt

IPCO is the world’s largest supplier of steel bake oven belts and has nearly 100 years’ experience of working with the bakery industry. This gives the company an understanding of production issues that goes beyond belts themselves, as IPCO global product manager Marko Leber explains.

The primary role of an IPCO steel bake oven belt is to convey goods through a continuously operating oven. The high thermal conductivity of this type of belt, whether solid or perforated, concentrates heat onto the product to achieve the desired crisp base, and the smooth, flat surface ensures a clean discharge at the end of the line with minimal risk of damage to fragile products.

A high-quality bake oven belt will have key mechanical properties – flatness, straightness – ‘engineered in’ at the production stage to ensure that it runs through the oven as it should. Consistency of colour is important too; dark areas absorb heat while light, shiny areas reflect it, so uneven belt colour could result in an uneven bake. This has to be engineered into the belt too.

In short, the quality of the manufacturing process – the transformation of a length of cold rolled carbon steel band into a high precision component – determines the long-term reliability of a bake oven belt and, in turn, the productivity, quality and profitability of the overall bake oven line.

Maintenance procedures

Maintenance requirements are relatively low compared with other belt materials. Solid and perforated steel belts are by their very nature highly durable and resistant to stretching and this alone keeps downtime to a minimum. A premium quality belt will also display good tension and tracking characteristics, which is key to reliable, trouble-free operation.

So, what maintenance does a steel belt need? Aside from regular checks, more of which in a moment, lubrication and cleaning are the two most important maintenance tasks.

Lubricant is essential as well as reducing friction. It helps eliminate risk of rust caused by condensation, it reduces wear, prevents belt distortion and, ultimately, leads to a longer belt life. It also helps to maintain a regular belt colour for an even bake.

The easiest way to apply a lubricant is via graphite skid bars, which deliver a gradual deposit of graphite to the inside of the belt. IPCO graphite skid bars are available for all standard belt widths.

If, for any reason, a skid bar cannot be used, graphite should generally be applied to the inside of the belt once a month for the first three months after installation, then every three to six months. If graphite is not permitted, specially selected oils can be used instead.

Cleaning is usually carried out using rotating brushes, with the application of scrapers as necessary. The brushes should be adjusted to apply gentle cleaning of the belt surface.

Ineffective cleaning will result in a build-up of carbon deposits on the baking side of the belt, leading to less than perfect products and, ultimately, a risk to health due to the presence of hazardous acrylamide.

A range of factors including belt type, end product, oven type and personal preference will determine the most effective approach to the removal of carbon deposits and will usually involve the application of chemicals, dry ice or detergents and great deal of manual input. It’s a task that cannot be ignored if an oven is to produce high quality goods.

Of course, some issues go beyond what could be termed ‘everyday’ maintenance and this is where our service support operation comes in.

IPCO service support

One of the unique strengths of IPCO is our ability to offer maintenance support that looks beyond the belt. For some customers, belt supply is all that’s needed, but for others we support the OEM or end user with a full range of conveyor components, from drums, sheaves and shafts to tracking systems, break points and graphite stations.

We understand how a belt interacts with the other components that make up the system as a whole. For our service teams, analysis of belt condition can paint a clear picture of how that system is performing.

It’s almost always the case that any issue with belt condition is the symptom of another problem, not one in its own right. Once the cause has been identified and rectified, we can return our attention to the belt itself and take whatever remedial action may be necessary to make sure that it’s in a condition to perform reliably for years to come.

For example, if side wandering is occurring, this can often cause the belt to come into contact with the structure or another rigid object, resulting in burrs. Wavy belt edges could be another indication of side wandering, or of uneven temperature in the oven. It can also indicate uneven pressure from the belt cleaner or scraper, or a belt scraper that is wider than the belt itself. We look for deformations in the belt, which could suggest problems with drums, belt supports or other parts coming into contact with the belt. Remedial actions include cleaning the drums, cleaning or replacing belt supports, and checking scrapers, rollers
and belt
tensioning.

We also inspect the underside of the belt, as any scratches could indicate worn or damaged belt supports or safety scrapers.

In one recent case, a customer asked us to look at belt tracking problems they were experiencing. They believed they’d probably need a new belt but wanted us to identify the root cause of the problem first.

As it turned out, the condition of the belt itself was not a concern but it was clear to our engineers that certain components were incapable of providing the reliability and performance that could be expected of modern conveyor equipment. The surfaces of the drums, for example, were no longer suitable for effective belt tracking.

We were able to retrofit a range of new components including inlet and outlet drums, tracking devices, a graphite station and a cleaning brush and scrapers, and retain the existing belt. The customer ended up with a state-of-the-art conveyor system capable of delivering significantly improved productivity, at a cost 25% less than it would have been for a new belt.

Preventative Maintenance Agreements

While trouble-shooting is a great way of supporting customers, prevention is obviously better than cure. By offering Preventative Maintenance Agreements (PMAs), we aim to identify risks of failure before they have chance to disrupt production.

Inspection work will cover all major system components. We check that terminal drums, rollers and skid bars are aligned horizontally and at right angles to the center line of the longitudinal axis of the oven line. We check that terminal drums and rollers are rotating freely and that tension and tracking devices are operating as they should be.

As a company we have fully trained and equipped service teams on the ground in all key markets, including Africa. This means we can provide a quick response to any service or repair needs, and that work is carried out by qualified people with a real understanding of customers’ needs and values.

Local teams can call on the support of IPCO’s Special Engineering team, experts who can be sent anywhere in the world to troubleshoot issues and provide specialist support.

We also support customers in the form of technician training, either on-site or at our regional headquarters in Johannesburg. Subjects can be tailored to requirements, but will typically focus on best practices in belt maintenance, repair techniques and use of the QuickTools range, all specially designed to make repair work as efficient as possible. BR

IPCO - www.ipco.com/bake