When a composite manufacturing process works well during development but struggles in production, it does not necessarily mean the original process was unsuccessful. More often, production introduces a wider range of conditions and exposes variables that were less significant, more tightly controlled or simply less visible during development.
Moving from development to production introduces new challenges. Changes in material batches, ambient conditions, tooling, equipment, cycle times and operator practices can all influence the final component. A process that produces good results under controlled development conditions may not deliver the same level of consistency when these variables change.
The challenge is not simply to produce a successful composite component once, but to establish a manufacturing process that consistently delivers the required quality, repeatability and performance at production scale. Understanding how process variables interact, identifying the critical parameters and establishing effective process controls are essential to making that transition successfully.
What Changes When a Composite Process Moves into Production?
During process development, individual parts often receive a high level of attention. Materials may be carefully prepared, experienced engineers and technicians are closely involved, and there is usually more opportunity to observe the process, investigate unexpected behaviour and make adjustments between trials.
The production environment is different. The same process may need to be carried out by multiple operators, materials need to move efficiently through the factory and equipment and tooling are subjected to repeated manufacturing cycles. Normal changes in ambient conditions, material batches and production schedules also become part of everyday manufacture.
The fundamental process may remain unchanged, but the range of conditions it must accommodate becomes wider. If the acceptable processing window is narrow, or has not been fully understood during development, normal production variation can expose weaknesses that were not apparent during initial trials.
This is one of the key differences between demonstrating technical feasibility and establishing a robust production process.
Why Does Process Variability Become More Significant in Production?
Variation exists in every manufacturing process. For liquid composite moulding processes such as Resin Transfer Moulding (RTM), Vacuum Resin Transfer Moulding (VRTM), resin infusion and Direct Infusion™, potential sources include resin temperature and viscosity, mix ratio, injection pressure, flow rate, vacuum integrity, tool temperature, reinforcement permeability, material condition and operator technique.
During development, some of this variation may be managed without being formally recognised. An experienced technician may respond to what they see happening during the process; materials may receive additional preparation, or an engineer may make an adjustment between trials. These interventions are valuable during development because they can help establish what the process needs.
However, if successful manufacture continues to depend on those interventions, increasing production can become difficult. The knowledge being used to maintain the process needs to be understood and, where appropriate, translated into measurable parameters, defined operating windows or process controls.
Production does not necessarily create variability. In many cases, it makes existing variability more visible.
Which Process Variables Affect Composite Manufacturing Repeatability?
There is no universal set of parameters that determines whether every composite manufacturing process will be repeatable. The critical variables depend on the component, material system, tooling, manufacturing method and required outcome.
For liquid composite moulding, pressure, flow, temperature and vacuum are often important. Resin condition and viscosity can influence how material moves through the reinforcement, while tool temperature, reinforcement permeability and vacuum conditions can alter process behaviour even when equipment settings remain unchanged.
The relationship between these variables is also important. A change in resin temperature, for example, can affect viscosity, which can then influence flow behaviour and fill time. Looking at one parameter in isolation may therefore provide only part of the picture.
The objective during process development is to determine which variables matter to the particular process, how they interact and what an acceptable manufacturing window looks like.
How Much Does Operator Dependency Affect Composite Manufacturing?
Experienced operators are an important asset in composite manufacturing. Their ability to recognise changes in material behaviour, identify developing problems and understand what is happening during a manufacturing cycle can provide valuable insight into the process.
The challenge arises when successful manufacture depends heavily on that individual experience. If one operator can consistently achieve the required outcome while another trained operator struggles, it is worth investigating what the experienced operator is seeing, interpreting or adjusting differently.
That knowledge can help identify aspects of the process that have not yet been sufficiently defined. There may be a parameter that needs to be measured, a limit that needs to be established or a condition that could be controlled more effectively.
The aim is not to remove people from composite manufacturing. It is to use their expertise to develop a process that supports operators in achieving consistent results, rather than requiring them to continually compensate for underlying variation.
Why Can the Same Machine Settings Produce Different Results?
Following the same procedure or using the same equipment recipe does not necessarily mean that the manufacturing conditions are identical.
A machine setpoint defines what the equipment has been instructed to do. Measurement provides information about what is actually happening within the process. Two manufacturing cycles could therefore use the same nominal injection pressure while experiencing different resin temperatures, flow behaviour, vacuum conditions or pressures within the mould.
From the machine settings alone, the cycles may appear identical. In reality, the conditions experienced by the component may be different. This is why greater process visibility becomes increasingly valuable as manufacturers move towards repeatable production.
Measuring the parameters that matter provides a way to compare cycles, recognise variation and understand the relationship between process behaviour and the finished component.
How Do You Know If a Composite Process Is Ready for Production?
Production readiness cannot be established from one successful component. Confidence is built by demonstrating that the process can deliver the required result across repeated manufacturing cycles and under conditions that are representative of production.
This means understanding which variables influence the outcome and establishing whether those parameters can be measured and, where necessary, controlled. It also means challenging the process across different material batches, operators and realistic environmental conditions, rather than validating it only under ideal development conditions.
Tooling and equipment also need consideration. A process may be well understood, but the production system still needs sufficient capacity, accuracy, control and process visibility to maintain the required conditions at the intended component size and production rate.
The objective is not to eliminate all variation. It is to understand and control the process sufficiently that normal manufacturing variation does not prevent the required outcome from being achieved.
How Do You Move a Composite Process from Development to Production?
There is rarely a single step between successful development and production. Manufacturing confidence is built progressively through process understanding, measurement, control, repeatability and validation.
Trials can be used to investigate how the process behaves and establish which parameters influence the outcome. Measurement then provides greater visibility of those variables, while appropriate control strategies help maintain critical conditions within the required manufacturing window. Repeated cycles and representative production trials provide the evidence needed to determine whether that approach is sufficiently robust.
Once those requirements are understood, the production solution can be engineered around the process. Depending on the application, this may involve tooling, resin conditioning, mixing and metering, vacuum technology, pressure and flow control, in-mould sensing, automation and data capture.
The aim is not simply to take development equipment and make it bigger or faster. It is to understand what the process requires and develop the manufacturing system needed to deliver it consistently.
What Does This Look Like in Practice?
Our work with Artemis Technologies demonstrates how process development can support the move towards repeatable production.
Over approximately three years, Composite Integration worked alongside the Artemis Technologies engineering team to optimise the resin infusion process for a critical carbon fibre epoxy composite component. The programme progressed through manufacturing trials, infusion process optimisation and the development of repeatable manufacturing parameters before integrating a customised CIJECT® 2 resin infusion system and validating the process for production.
The result was a repeatable resin infusion process capable of achieving laminate quality comparable to prepreg manufacture, while significantly reducing manufacturing time. Importantly, the solution was not simply a piece of equipment. It combined the process knowledge developed throughout the programme with manufacturing technology configured around the requirements of the component.
Explore our case study: From Process Development to Production: Optimising Composite Component Manufacturing for Artemis Technologies.
What if the Composite Process Is Already in Production?
These principles are equally relevant to established manufacturing processes. A manufacturer may already be producing components successfully but experience variability, increasing scrap or rework, inconsistent cycle times, excessive operator intervention or difficulty meeting changing production requirements.
In some cases, these issues emerge as volumes increase or a process is transferred between teams or sites. In others, a process may have relied successfully on operator knowledge for many years, but changing production requirements make that approach increasingly difficult to sustain.
Returning to the fundamentals of process understanding, measurement and control can help identify where variation is entering the process and whether changes to the manufacturing approach, tooling, equipment or control strategy could improve performance.
How Can Composite Integration Help?
At Composite Integration, we don't start with a machine. We start with the manufacturing challenge.
Our engineers work in partnership with customer teams to understand the component, materials, existing process and production requirements before determining the appropriate manufacturing approach. This can begin with feasibility and process development, or with evaluating and optimising a process already in production.
Our capabilities span process development and trials, tooling, CIJECT® resin mixing, injection and infusion technology, CIVAC® vacuum systems, in-mould measurement, process monitoring and control, automation, validation, installation, training and ongoing technical support.
Bringing these capabilities together allows the equipment and wider manufacturing system to be developed around the requirements of the process, rather than expecting the process to adapt around the equipment.
Whether the challenge is moving a new component towards production or improving an established manufacturing process, the principle is the same: understand why the process works, then create the conditions required to make it happen repeatedly.
Is Your Composite Process Ready for Production?
Our Composite Scale-Up Readiness Checklist provides 12 practical questions to help you consider process understanding, measurement, control, repeatability and production readiness.