- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views: 0 Author: SINOBAKE-Johnson Publish Time: 2026-11-03 Origin: Site
Why do some biscuits shrink after cutting, while others lose their patterns after moulding? The answer lies in the relationship between dough rheology and forming mechanics.
A biscuit may appear simple. Its shape, thickness, weight and surface pattern are the result of a surprisingly complex interaction between food science and mechanical engineering.
Consider two products.
One is a soda cracker, formed from a continuous dough sheet and cut into individual pieces.
The other is a high-fat short-dough biscuit, pressed directly into engraved mould cavities to reproduce a detailed surface pattern.
Both require dimensional accuracy. Both require consistent piece weight. Yet the physical mechanisms responsible for achieving these results are fundamentally different.
This distinction is often overlooked in industrial biscuit manufacturing.
The accuracy of a cutting operation depends heavily on the dimensional stability of the dough sheet. The accuracy of a moulding operation depends on how the dough deforms, fills the cavity and retains its shape after release.
In both cases, the machine provides the mechanical conditions. The dough determines how it responds.
To understand forming performance, we need to examine three interconnected phenomena:
Dough relaxation and the dissipation of internal stress.
Elastic recovery and dimensional stability after deformation.
Forming mechanics and their influence on piece weight, geometry and surface definition.
These are not isolated laboratory concepts. They directly influence production efficiency, product consistency and the economic performance of a biscuit factory.
Before discussing dough relaxation, it is important to understand the two fundamental forming mechanisms used in biscuit production.
They may both involve rotating rollers, but they solve different engineering problems.
Rotary Cutting
Sheet-based forming
A continuous dough sheet passes through a cutting system. The cutting roll defines the product outline and separates individual dough pieces from the surrounding sheet.
Cavity-based forming
Plastic short dough is forced into engraved cavities on a moulding roll. A scraper removes excess dough, and the formed pieces are transferred onto an extraction belt.
Rotary cutting is commonly used for semi-sweet biscuits, hard-dough biscuits and crackers.
The process generally involves:
Dough mixing and preparation.
Initial sheeting.
Progressive thickness reduction through gauge rolls.
Dough relaxation.
Rotary cutting and, where required, surface docking or embossing.
Scrap separation and return.
Transfer of individual dough pieces towards the oven.
The dough sheet is the starting point of the forming operation.
Its thickness, density, internal stress distribution and dimensional stability determine how consistently the cutting geometry can be reproduced.
The cutting die must also account for the dimensional behaviour of the dough during processing and baking.
Baker Perkins specifically identifies shrinkage allowance, docking, die geometry and surface finish as important considerations in rotary cutting design.
Biscuit, Cookie & Cracker+2
Rotary moulding is principally associated with short doughs, including many high-fat biscuit and shortbread formulations.
The dough is supplied to the moulding area, where mechanical pressure drives it into the engraved cavities.
The scraper removes excess dough from the mould surface, while the extraction system transfers the moulded pieces away from the roll.
Unlike rotary cutting, conventional rotary moulding does not generate the same surrounding lattice of scrap dough.
The two technologies therefore require different approaches to weight control, dough preparation and defect diagnosis.
ScienceDirect+1
Dough relaxation is one of the most important concepts in hard-dough processing.
Yet it is often misunderstood as simply allowing dough to rest for a certain number of minutes.
In engineering terms, relaxation describes the time-dependent reduction of internal stress under a maintained deformation condition.
When dough passes through gauge rolls, it experiences compression, extension and changes in its internal structure.
The gluten-containing matrix of hard dough can develop residual stresses as a result of this mechanical working.
When the dough is subsequently allowed to relax, some of these stresses dissipate.
Imagine a dough sheet immediately after its final gauging operation.
Although it may appear smooth and uniform, it may still contain internal stresses.
If the sheet is cut immediately, some of those stresses may be released as the dough pieces become mechanically separated from the surrounding sheet.
The result can be dimensional recovery.
For example:
A rectangular dough piece may become shorter.
A circular outline may become slightly distorted.
The distance between adjacent pieces may change.
The dimensions of the cut dough pieces may become less consistent.
This is why industrial hard-dough lines commonly incorporate a relaxation conveyor between gauging and cutting.
The conveyor allows the dough sheet to relax before the cutting operation.
The process is not simply about waiting. It is about managing the mechanical history of the dough.
A relaxation conveyor can be designed to allow the dough sheet to travel in a controlled, relatively unrestrained condition.
Some industrial arrangements use a controlled wave or sag in the sheet to provide additional residence time.
The purpose is to reduce the residual stress generated during thickness reduction before the cutting operation.
The actual relaxation conditions depend on:
Flour protein characteristics.
Water absorption and hydration.
Mixing intensity.
Number and degree of gauging reductions.
Dough temperature.
Conveyor speed and residence time.
The important principle is that relaxation should be evaluated in relation to the complete sheeting process, not as an isolated time setting.
ScienceDirect+2
Elastic recovery is closely related to relaxation, but the two concepts should not be confused.
Relaxation describes the reduction of internal stress over time.
Elastic recovery describes the partial return of a material towards its previous dimensions after an applied deformation is reduced or removed.
Dough exhibits both elastic and viscous behaviour. Its response depends on the formulation, temperature, moisture content and mechanical history.
Consider a dough sheet passing through a pair of gauge rolls.
The rolls reduce its thickness and impose mechanical deformation.
After leaving the rolls, the sheet may recover partially in thickness or change its length and width.
This behaviour can be particularly relevant when the dough has undergone substantial mechanical working.
In rotary cutting, dimensional recovery can influence the relationship between the cutting die and the final dough piece.
In rotary moulding, the problem is different.
The dough is compressed into a cavity, and the important question becomes whether it can reproduce the engraved geometry and retain that geometry after release.
This is why a good forming process must balance deformability with structural stability.
No.
Some degree of elastic recovery is a normal characteristic of viscoelastic materials.
The engineering concern is whether the magnitude and timing of recovery are compatible with the required product dimensions and forming tolerances.
A dough that recovers excessively may produce dimensional variation.
A dough that is too resistant to deformation may not fill the mould completely.
A dough with insufficient structural stability may deform during transfer.
The objective is not to eliminate elasticity, but to manage its influence on the process.
One of the biggest mistakes in biscuit production is treating dough consistency as a simple matter of adding more or less water.
In reality, mouldability is influenced by the interaction of several ingredients and processing variables.
For high-fat short doughs, fat distribution and the stability of the creaming phase are particularly important.
During mixing, fat, sugar, water and other ingredients interact to form a dough structure with specific plastic and cohesive characteristics.
The quality of this structure affects how consistently the dough can be fed into and compressed within the mould cavities.
Research published in Foods in 2021 examined the relationship between creaming stability and the quality attributes of rotary-moulded biscuits.
The study highlighted the importance of mixing conditions, sugar particle size and creaming stability in determining dough properties and finished biscuit characteristics.
This is a significant finding for industrial manufacturers.
A moulding defect may originate much earlier than the moulding machine itself.
If the creaming phase is unstable, the resulting dough may show variations in its structural characteristics and forming behaviour.
Consequently, changing the moulding pressure or scraper position may not solve the underlying problem.
The more effective approach is to examine the complete chain:
Ingredient Preparation → Creaming Stability → Dough Development → Mouldability → Finished Biscuit Quality.
MDPI+1
Piece weight is not determined by one machine setting.
It is the result of material properties interacting with forming geometry.
However, the factors influencing weight differ substantially between cutting and moulding.
In sheet-based forming, the weight of an individual dough piece can be approximated by:
\[ m=\rho \times A \times h \]
Where:
\(m\) = dough piece mass
\(\rho\) = dough density
\(A\) = projected cutting area
\(h\) = average sheet thickness
A more practical expression for industrial process monitoring is:
\[ m=q_A\times A \]
Where \(q_A\) is the mass per unit area of the dough sheet.
This reveals an important engineering point.
Two dough sheets may have the same nominal thickness but different mass per unit area because of differences in density, aeration or internal structure.
Therefore, thickness measurement alone cannot always explain piece weight variation.
A more complete quality-control programme should monitor:
Sheet thickness across the working width.
Sheet mass per unit area.
Dough piece weight by lane or position.
Cutting die geometry.
Dimensional recovery after cutting.
In cavity-based forming, a simplified relationship is:
\[ m=\rho \times V \times \eta \]
Where:
\(m\) = dough piece mass
\(\rho\) = dough density
\(V\) = nominal cavity volume
\(\eta\) = effective cavity filling factor
The mould cavity defines the intended geometry, but the actual piece weight depends on the extent to which the cavity is filled.
This is where dough consistency, feeding stability and scraper adjustment become critical.
A dough that is too firm may not completely reproduce the cavity geometry.
A dough that is excessively soft may create difficulties in scraping, release and shape retention.
The objective is to achieve consistent cavity filling without compromising the structural integrity of the formed piece.
The scraper is an important control element in rotary moulding.
It removes excess dough from the surface of the moulding roll while helping define the amount of dough retained in each cavity.
Its adjustment influences the relationship between the dough remaining in the cavity and the excess dough removed from the roll surface.
An unsuitable scraper setting may contribute to:
Excessive dough remaining on the mould surface.
Incomplete or inconsistent cavity filling.
Weight variation between pieces.
Irregular edges.
Reduced pattern definition.
The scraper should therefore be adjusted in conjunction with dough consistency, feeding conditions and mould geometry.
It should not be treated as an independent weight-control device.
In modern forming equipment, feeding, forming and conveying must operate as a coordinated system.
Independent motor control provides flexibility in establishing the appropriate relationship between these movements.
For example, a rotary moulding system with independently controlled feeding, moulding and conveyor drives allows the operator to adjust the three movements separately.
This is valuable when processing different dough formulations or product geometries.
In rotary cutting, independent control of the cutting roll and conveyor similarly supports adjustment of their relative motion.
However, independent drives do not automatically guarantee accurate piece weight.
They provide controllable mechanical conditions. Consistent weight still depends on stable incoming material and verified process settings.
A mould can be manufactured with extremely fine details, but that does not mean every dough piece will reproduce those details accurately.
Pattern definition depends on three stages:
First: Cavity Filling
The dough must enter the engraved areas completely.
If the dough is too firm or feeding is unstable, fine details may not be reproduced.
Second: Shape Retention
After the moulding pressure is reduced, the dough must retain the geometry imposed by the mould.
Excessive recovery or insufficient structural stability may affect the final profile.
Third: Controlled Extraction
The formed dough piece must separate from the mould without stretching, tearing or losing its intended shape.
8
These stages are closely connected.
For example, a biscuit with blurred decorative details may not necessarily have a defective mould.
The actual cause may be incomplete cavity filling, unsuitable dough consistency, scraper adjustment or unstable extraction.
Baker Perkins' published die-design guidance also emphasises that rotary mould design must account for forming and baking behaviour to achieve the intended finished-product size, shape and weight.
Biscuit, Cookie & Cracker+1
Forming a dough piece is only half of the process.
The other half is releasing it successfully.
During rotary moulding, the dough must first make sufficient contact with the mould cavity to reproduce the engraved shape.
It must then separate from the mould and remain on the extraction system.
This creates a balance between adhesion, cohesion and mechanical release.
Three physical properties are particularly important.
Adhesion
The interaction between the dough surface and the mould surface.
Cohesion
The ability of the dough structure to remain intact during deformation and separation.
Release Mechanics
The effect of belt movement, roller geometry, belt tension and relative motion on the separation of the dough piece.
In conventional rotary moulding, cotton canvas extraction webs are widely used to support dough-piece release.
In SINOBAKE's forming equipment, the conveying arrangements differ according to the forming principle.
The cutting process uses a dedicated food-grade cutting conveyor belt, while the moulded dough pieces are transferred onto a cotton canvas belt for onward transportation.
These are not interchangeable conveyor functions.
In rotary cutting, the belt supports the continuous dough sheet during cutting.
In rotary moulding, the extraction web participates in the transfer of individual dough pieces from the moulding roll.
GEA's technical information similarly identifies automatic belt tensioning and tracking, extraction quality and controlled forming-roll operation as important aspects of rotary moulding.
GEA+2
Dough behaviour is the foundation of forming quality.
Mechanical stability is what allows that quality to be reproduced consistently.
Several engineering features are particularly important in modern biscuit forming equipment.
Independent motor control provides greater flexibility in coordinating the forming roll and conveyor.
In more advanced moulding configurations, feeding, moulding and conveying can each be controlled independently.
This allows the production team to establish suitable speed relationships for different product requirements.
Servo-driven forming rolls provide precise motion control and support accurate speed adjustment.
Their benefits depend on the complete control system, mechanical transmission, feedback and commissioning quality.
Pneumatic pressure regulation provides a means of managing the mechanical loading applied during forming.
It is particularly relevant when processing dough with different physical characteristics.
Controlled gap adjustment allows the operator to establish repeatable mechanical settings.
It is important to understand that gap and pressure are different engineering parameters.
Gap defines the relative geometric position of the relevant components, while pressure describes the applied mechanical force or loading condition.
Stable belt tension and alignment are essential for maintaining consistent product transfer.
Pneumatic tensioning and tracking arrangements support conveyor stability and reduce the risk of belt deviation.
Food-contact materials, accessible cleaning surfaces, suitable guarding and reliable mechanical components all contribute to industrial production requirements.
These features should not be viewed as decorative specifications.
They form part of the engineering system that supports repeatable production.
A common mistake in industrial production is to adjust the machine before understanding the material.
A more effective approach is to identify whether the problem originates from dough preparation, mechanical forming or product transfer.
Observed problem | Possible underlying mechanism | Recommended investigation |
|---|---|---|
Dough sheet shrinks after gauging | Residual stress and elastic recovery | Review gauging reductions, dough temperature and relaxation conditions |
Cutting dimensions vary | Sheet thickness or mass distribution | Measure across the working width and inspect cutting synchronisation |
Dough pieces have inconsistent weight | Uneven sheet mass per area | Check dough density, thickness and lane-by-lane weight |
Moulded biscuits have incomplete patterns | Incomplete cavity filling | Investigate dough consistency, feeding and scraper adjustment |
Dough sticks to the mould | Unsuitable surface interaction or release conditions | Inspect dough condition, mould surface and extraction web |
Moulded edges become distorted | Inadequate shape retention or unstable extraction | Review dough plasticity and transfer conditions |
Finished dimensions differ from dough-piece dimensions | Baking expansion, shrinkage or moisture loss | Compare dimensions before and after baking |
A production team should not rely entirely on visual inspection.
For rotary cutting, a useful control plan includes:
Dough sheet thickness measurement.
Mass per unit area.
Piece weight distribution.
Cutting dimension measurements.
Scrap dough recovery condition.
For rotary moulding, the control plan should include:
Dough temperature and consistency.
Weight variation across mould cavities.
Scraper setting.
Mould surface condition.
Extraction stability.
Pattern definition.
For both processes, the coefficient of variation can be used to evaluate piece-weight consistency:
\[ CV(\%)=\frac{s}{\bar{x}}\times100 \]
Where:
\(s\) = Standard deviation.
\(\bar{x}\) = Mean dough piece weight.
A lower CV indicates more consistent weight distribution.
The acceptance limit should be established according to the product specification, production target and customer requirements.
The most important principle is to measure before adjusting.
Changing several machine parameters simultaneously may temporarily improve the appearance of the product, but it makes it difficult to identify the actual cause of the problem.
The quality of a biscuit is not fully determined when it leaves the forming machine.
Baking introduces another series of physical and chemical changes.
As the dough enters the oven:
Moisture begins to migrate and evaporate.
Fat melts and redistributes.
Leavening reactions generate gases.
The dough structure changes as starch and proteins undergo thermal transformations.
The product develops its final texture, colour and dimensions.
This means that an accurate dough piece does not automatically guarantee an accurate finished biscuit.
For example, dimensional changes after baking may result from the interaction between dough formulation, initial moisture, thickness, leavening, oven temperature profile and baking time.
A comprehensive quality-control programme should therefore compare:
Measurement stage | What should be evaluated |
|---|---|
Before forming | Dough temperature and consistency |
After cutting or moulding | Piece weight and geometry |
Before oven entry | Piece positioning and dimensional stability |
After baking | Final dimensions, colour and surface quality |
After cooling | Finished weight, texture and dimensional consistency |
This approach provides a much clearer picture of where production variation originates.
Consistent biscuit production is the result of several carefully coordinated processes.
For sheet-based forming, dimensional stability depends on how the dough responds to mixing, gauging, relaxation and cutting.
For cavity-based forming, accuracy depends on dough plasticity, cavity filling, scraper control and reliable extraction.
Piece weight is governed by the relationship between material properties and forming geometry.
Pattern definition depends on how accurately the dough enters, reproduces and retains the shape of the mould.
And mechanical precision provides the conditions needed to reproduce these results consistently.
The most important lesson is simple:
A forming machine cannot compensate for every variation in the dough. And a well-prepared dough cannot deliver its full potential without the right forming technology.
At SINOBAKE, we approach biscuit production as an integrated engineering process.
From dough preparation and material handling to forming, baking and finished-product quality, every stage contributes to the final result.
We believe precision is not simply a machine specification.
It is the result of understanding the material, controlling the process and engineering every detail that matters.
SINOBAKE
Made with Precision. Built with Excellence.
TURNKEY BISCUIT & COOKIE & POTATO CHIPS & SILO DOSING PRODUCTION SOLUTIONS.
Website: www.sinobakesnacks.com
Johnson | VP Sales
WhatsApp: +86 159 1810 5286
