What are Rotary Moulder Belts?
Rotary moulder belts are a type of woven conveyor belt, predominantly made from cotton weave, that is used in the process of biscuit manufacturing.
The rotary moulder conveyor belt is usually used for short dough and cracker lines, to substitute the process of ‘sheeting’, ‘cutting’ and ‘gauging’ which are traditionally hand-based manufacturing methods.
Rotary belts are ‘endless belts’ in nature, due to their ‘seamless’ production properties, and are usually run on a ‘knife edge conveyor system’.
What are Knife Edge Conveyors?
Knife edge conveyor systems is a section of a conveyor system that is uniquely designed to transfer small objects (in this case, biscuit dough) from one part of the conveyor system to the next for the continuing production of biscuits.
The ‘knife edge’ is often rounded and may also be referred to as the ‘nosebar’.
The beauty of the knife edge section of the conveyor system is it’s ability to lightly transfer products through the conveyor system without breakage, or falling into gaps. This is a perfect solution for biscuit production as this limits the amount of cracks, and breakages within the dough during the production of the biscuit itself.
How are Rotary Moulder Conveyor Belts Used in Biscuit Making?
Once the dough for the biscuit or cracker is made, the next phase of the production is to move it into ‘shaping’. This is where you see the famous ‘McVities print on biscuits, or the unique design of a Malted Milk’.
These unique designs are a result of the rotary moulding process of biscuit production.
The rotary conveyor belt must have the optimum of ‘pull’ and ‘release’ abilities so that it can peel off the dough from the roller press onto the belt, and also release the formed biscuit shapes from the nosebar onto the oven conveyor belt without breaking or cracking the pre-cooked biscuits.
A quality manufactured rotary conveyor will ensure a ‘seamless transfer’ has been made whereby 100% of the dough is successfully ‘released’ from the conveyor belt at the nosebar point, and onto the next phase of biscuit production.
Key Requirements for Rotary Moulder Belts
Endless belts such as rotary moulder belts are typically made from three key materials. These vary between cotton, nylon and polyester. The belting material type used is based on the biscuit manufacturers requirements. For example, depending on the biscuits fat and grease content within the dough, a specific material may be required depending on the density of the dough.
This is because of the aforementioned requirements for optimum pull and release between the different phases of the conveyor belt. Nylon, with a 6% moisture regain, or polyester with 4% moisture regain are more suitable for less fatty dough biscuit and crackers.
Conversely, cotton conveyor belts, with a higher moisture regain are naturally more suitable to biscuits and crackers with a higher fat density. This is due to the belts ability to absorb the dough perfectly onto the conveyor from the rollers, with also the ability to release the biscuits seamlessly at the other end.
Typically, for thinner biscuits or crackers, a thinner conveyor belt, with less ‘ply’ will be used to allow for a more perfect release from the knife edge/nosebar.
Most belting will have some form of nylon incorporated into the belt weave itself as this helps with avoidance of abrasion and increases the shelf life of the biscuit conveyor belt.
Types of Weaves for Conveyor Belts
To help with the requirement for pull and release, different types of weaving of the conveyor belt can be used. When viewing a non-coated biscuit or cracker from the bottom, you will notice a pattern. This is the pattern from the weave of the conveyor belt imprinted onto the biscuit.
There are three main types of weaving methods for woven conveyor belts:
Traditionally used on conveyor belting, and the most common form of weave. The plain weave provides a consistent performance in biscuit production, which makes it a versatile solution for all conveyor belting requirements.
Twill Weave/Herringbone Weave
Both the names twill weave and herringbone weave mean the same thing within conveyor belt weaving. This distinct pattern is reflective of herringbone stitched materials in fashion. The twill weave is highly regarded as a useful solution for heavy dough biscuits as the weave helps with the extraction of the biscuit/cracker from the mould roller.
Cross Twill Weave/Broken Twill Weave
Again, these particular belting weave has two names; the cross twill weave and the broken twill weave. Both refer to the same type of belting weave.
The cross twill weave provides an easier release from the nosebar due to its air permeability, which allows pockets of air to form, and reduces the contact area between the conveyor belt and the biscuit
Getting the Best Out of Your Rotary Belt Manufacturer
It’s imperative that when sourcing a rotary belt manufacturer, that you identify the requirements of rotary conveyor belt prior to procurement of the belt. The best conveyor belt manufacturers will look to assess your manufacturing situation upfront in order to delivery abespoke, and high-quality conveyor belt system for your production needs.