Substantial modification of machinery under Regulation (EU) 2023/1230

Because substantial modification is a critical theme for manufacturers and users

In real life a machine rarely remains identical to the initial configuration. It is adapted to new formats, connected to other machines, updated in the software, equipped with new sensors, integrated in a line, modified for production needs or higher performance. All this is normal. But not all changes have the same weight from the point of view of CE compliance.

The question becomes critical when the intervention changes the risk profile of the machine. An account is to replace a worn component with an equivalent component. Other account is to increase movement speed, turn a manual loading into automatic load, add a motorized axis, change safety logic, install a robot, change the scope of a lifting system or introduce remote access capable of altering safety-related parameters.

In these cases the question should not be: “the machine already had the CE marking?”. The correct question is: “Is the modified machine still covered by the risk assessment and the original declaration of conformity?” If the answer is no, the company must stop and deal with the change with a structured technical process.

This is particularly important for complex lines in packaging, food, pharmaceuticals, cosmetics, automation, palletising, materials handling, special-purpose machinery and custom systems. Modifications are frequent and often involve several parties: the original manufacturer, integrator, user, robot supplier, control panel builder, PLC programmer, maintenance technician and machinery safety consultant. If responsibilities are not defined in advance, technical risk can quickly become legal and contractual risk.

What Machinery Regulation (EU) 2023/1230 says

Regulation (EU) 2023/1230 introduces a specific definition of substantive modification to Article 3, 16. The text speaks of a modification of a machine or related product, carried out by physical or digital means after placing on the market or commissioning, not foreseen or planned by the manufacturer, which affects safety by creating a new danger or increasing an existing risk.

To be substantial, the change must also require at least one of the following operating conditions:

• the addition of guards or protective devices that involve the modification of the existing safety control system, or
• the adoption of additional protective measures to ensure the stability or mechanical strength of the machine or the related product.

This setting is important for two reasons.

First, the Regulation does not consider any modifications substantial, but only that which exceeds a precise technical threshold.

Second: the concept also expressly includes digital media. Then a software modification, a new PLC function, firmware update or control logic modification can be as relevant as a mechanical intervention if they affect safety.

The 26 also clarifies the basic principle: repair and maintenance that do not affect compliance with the essential requirements of safety and health protection should not be considered substantial changes. On the contrary, if the change requires new and significant protective measures, those who carry out it must carry out a new conformity assessment before the modified product is placed on the market or put into service.

When a change becomes substantial

A surface checklist is not enough to properly evaluate a change. It serves a technical reasoning based on risk, intended use, state of the art and impact of intervention on the machine. The most effective sequence is this:

1. Identify the original configuration of the machine: CE statement, instructions for use, technical file available, electrical schematics, limits of use, performance, safety functions and applied standards.
2. Describe the planned or already implemented modification: added parts, removed parts, modified logic, new functions, new actuators, new interfaces, new operating conditions.
3. Check if the modification was provided by the original manufacturer: declared options, compatible accessories, assembly instructions, permissible performance range, authorized software updates.
4. Perform a risk assessment of the modified configuration, comparing the situation before and after the intervention.
5. Establish if a new danger arises or increases an existing risk.
6. Evaluate if new protective measures are needed to reduce the risk by changing the safety control system, or additional measures for stability or mechanical strength.
7. Define whether the change is substantial and document the decision with a documented technical justification.

The decisive point is the risk assessment. The Regulation requires that the manufacturer establish the limits of the machine, individual hazards, stigmas and assess the risks and apply risk reduction measures according to the principles of safety integration. The same method must be adopted by those who substantially modify the machine, because it is treated as a manufacturer for the purposes of the Regulation.

In practice, a change can become substantial when it changes at least one of these elements: machine function, intended use, access mode to hazard zones, speed, strength, energy, flow, stability, control logic, safety functions, interactions with other machines, operator exposure, maintenance mode, automatic behaviour or level of autonomy.

Who becomes a manufacturer and what obligations it assumes

The strongest consequence is provided for in Article 18 of the Machinery Regulation. A natural or legal person who makes a substantial modification to a machine or related product is considered to be a manufacturer for the purposes of the Regulation. This means that it no longer acts as a maintenance technician, user or supplement: it assumes the obligations of the manufacturer for the modified machine or, if the change concerns only a part of a set, for the machine or the related product concerned, as demonstrated by the risk assessment.

The subject carrying out the substantial modification must ensure and declare, under his sole responsibility, that the modified machine complies with the applicable requirements of the Regulation. It must also apply the relevant compliance assessment procedure provided for in Article 25.

In operational terms, the obligations include at least:

• draw up or update a full risk assessment on the modified configuration;
• verify all the essential health and safety requirements of Annex III;
• define and validate risk reduction measures;
• update or rebuild technical documentation according to Annex IV, Part A;
• verify the application of relevant harmonised standards or other appropriate technical specifications;
• perform necessary calculations, tests, inspections and validations;
• update instructions for use, safety information, electrical schematics, tires, hydraulics and software when relevant;
• draft the EU declaration of conformity of the modified machine;
• affix the CE marking in accordance with the applicable requirements;
• retain technical documentation and declaration of conformity for at least 10 years;
• involve a notified body when required by the machine category and the applicable evaluation procedure.

This aspect is often underestimated in the relationship between user and supplier. If a company in charge of a supplement to change a line, it is necessary to establish contrattually who designs the modification, who performs the risk analysis, who validates the safety functions, who updates the technical file, who signs the statement and who assumes the role of manufacturer of the modified machine or the whole concerned.

Physical, digital and software changes: the new point of attention

An important novelty of the Machinery Regulation is the reference expressed to changes by physical or digital means. This reflects the reality of modern machines: many changes no longer pass from carpentry, motors or guards, but from software, parameters, network, remote access, firmware, algorithms, recipes and control logic.

A software modification can become relevant when changing the safe behaviour of the machine. Typical examples: automatic speed change, new mode of operation, exclusion or redefinition of interlocks, different reset management, muting change, change of stop distances, upgrade of safety PLC, change of parameters affecting force, couple or stop space, remote access introduction with possibility to alter safety-related functions.

The theme is not to say that every software update is substantial modification. The point is that the software must be treated as part of the machine when it governs functions that affect the risk. If the upgrade was provided by the manufacturer, it does not change the intended use, it does not increase the risk and does not alter safety functions, it may fall into the maintenance or evolution planned. If you change functions, performance or risk conditions not covered in the original assessment, you need a specific assessment.

The documentation must therefore include management of software versions, safety programming logic when necessary, validation tests, backups, recovery criteria and access control. It is not bureaucracy: it is the basis to demonstrate that the modified machine maintains a proper level of safety.

Practical examples of substantial modification

The following examples do not replace a case-by-case assessment, but help to understand the correct method. The substantial modification is not decided by the name of the intervention, but by the technical effect on safety.

Example 1 – Adding a robot to an existing packaging machine

Scenario. A company uses a food packaging machine with manual loadinging. To increase productivity decides to add an anthropomorphic robot that takes the products from a tape and inserts them in the feeding area of the machine. The intervention includes new perimeter fences, interlocked doors, safety scanners, new interface electrical framework, modification of the PLC machine and connection to the line emergency stop circuit.

Technical evaluation. The change introduces new hazards: robotized movements, crushing, shock, trap, access to zones with automatic movements before non-existent, interactions with tape and downstream machine. It also changes the mode of use: the operator no longer loads manually in the same position, but works around an automated cell. To reduce the risks, guards, protection devices and a change in the existing safety control system are required.

Reasoned conclusion. In the absence of an original provision made by the manufacturer that exactly contemplated this integration, the case has strong characteristics of substantial modification. Those who carry out the integration or assume responsibility for it must evaluate the modified configuration, define the boundaries of the machine or assembly, validate the safety functions, update the technical file and manage the new CE compliance of the affected part or the whole, according to the outcome of the risk analysis.

Practical point. It is not enough to declare that the robot is marked CE. The robot is a product that is consistent in its perimeter, but the robot-machine-nastro-operator integration creates a new system with its own risks. Conformity of individual components does not automatically demonstrate the compliance of the modified set.

Example 2 – Increasing the capacity and speed of a lifting system

Scenario. A manipulator or small lifting system is designed to handle loads up to 80 kg. For production needs it is modified to manage loads up to 130 kg. The intervention provides replacement of the actuator, reinforcement of some elements, modification of the socket system, updating of the speed parameters and new control logic. The original structure was not designed for this flow.

Technical evaluation. The increase in the flow rate changes the maximum load, stresses, stability, energy of the movements and the risk in case of fall or loss of the load. It may be necessary to recalculate structure, fixings, gripping organs, brakes, stops, safety coefficients and stability conditions. If additional measures are needed to ensure stability or mechanical strength, the case falls directly into the logic of the definition of substantial modification.

Reasoned conclusion. The modification is potentially substantial because it alters an essential parameter of the machine and may require additional measures for stability and mechanical strength. The person carrying out the modification must assume the role of manufacturer of the modified machine or of the affected part, perform relevant calculations and tests, update instructions, markings, limits of use, declaration of conformity and technical documentation.

Practical point. Even when the change “works” in production, it does not mean that it is compliant. Compliance is demonstrated by analysis, calculations, tests and documents. In lifting, the empirical test does not replace the technical evaluation.

Example 3 – Modify auto machine software with remote access

Scenario. An automatic machine is already in service. To reduce cycle times, the PLC: software is changed, new accelerations, different axes sequence, remote management of recipe parameters and possibility to change some thresholds from HMI or via remote connection. The change does not include visible mechanical changes, but affects the behaviour of the machine.

Technical evaluation. The change is digital, but it can affect safety. If speed changes, stop times, synchronisms, muting, safety or logical distances related to guards and protective devices change, the original rating may not be more valid. They could change PLr, response times, minimum distances, possibility to avoid the damage and exposure level of the operator.

Reasoned conclusion. The change is not automatically substantial only because software. However, it may become if it creates a new danger or increases an existing risk and requires the adoption of new protective measures or changes to the safety control system. In any case, you need a documented evaluation, version management and validation of the functions involved.

Practical point. Software changes must be treated with the same discipline as physical changes when affecting safety. Those who intervene on the PLC or the safety PLC must know that it is not only “optimizing the cycle”: it can change the technical basis of the CE compliance.

Frequently Errors

How Waves Engineering supports manufacturers

Waves Engineering supports manufacturers, integrators and companies using machinery in evaluating changes on existing machines and lines. The goal is to give a defensive technical response: is the change substantial or not? If it is, what perimeter should be certified? If it is not, what evidence should be kept to demonstrate the correctness of choice?

The support may include document analysis, technical inspection, risk assessment according to EN ISO 12100, verification of control circuits related to safety, calculation and validation of Performance Level according to EN ISO 13849-1, verification of electrical schematics, definition of protective measures, instructions for use updating, technical file, EU declaration of conformity and support to CE marking.

The real value is to avoid two opposite errors: to underestimate a change that requires new compliance, or to treat as substantial an intervention that could be managed with a documented valuation more streamlined. Either way, you need method.

Recommended final CTA

Are you changing a machine, a production line or an existing plant? Before intervening on guards, PLC, safety PLC, robot, performance, flow or logic of operation, check if the change can be substantial. Waves Engineering can help you define the correct perimeter, update risk analysis, validate safety functions and prepare the technical documentation necessary for a solid and defenseable compliance.

FAQ

What is a substantial modification of a machine?

It is a physical or digital modification made after placing on the market or commissioning, not provided by the manufacturer, which affects safety by creating a new danger or increasing an existing risk and requiring new relevant protection measures according to Machinery Regulation (EU) 2023/1230.

A substantial modification requires a new CE marking?

Yes, when the change falls within the definition of the Regulation. Those who carry out it are considered manufacturer and must apply the relevant conformity assessment procedure, draw up the EU declaration of conformity and place the CE marking on the machine or on the affected scope.

Ordinary maintenance is substantial modification?

No, generally maintenance and repair that do not affect machine compliance to essential safety requirements are no substantial changes. The conclusion should however be documented if the intervention is technically relevant.

Can a software change be substantial?

Yes. The Regulation expressly speaks of changes by physical or digital means. If the software changes functions, performance, safety logic or risk conditions not provided by the manufacturer, it may become relevant for the purposes of substantial modification.

Who is responsible for the substantial modification?

The natural or legal person that carries out a substantial modification is considered the manufacturer for the purposes of the Machinery Regulation and assumes the manufacturer’s obligations for the machinery or the affected part.

Do you always need a notified body?

Not always. It depends on the category of the machine or the related product and the conformity assessment procedure applicable under Article 25 and Annex I of the Regulation.

If I change only one station of a line I need to remake the CE of the whole line?

Not necessarily. If the risk assessment shows that the change affects only a machine or a related product within the assembly, the obligations may be limited to that scope. If interactions within the assembly change, the scope of the assessment expands.

What is the most important document to prepare before editing?

The preliminary technical evaluation of the modification, with analysis of the risk before/after, affected scope, determination of whether the modification is substantial and documentary plan. Without this stage, CE management becomes fragile.