Quality in Series Production of Precision Turned Parts
In series production, the ability to manufacture parts in accordance with the documentation is by no means enough to ensure success.
What is crucial is the process’s ability to maintain the required parameters across all subsequent production batches throughout the entire project.
That is why, at SABNER, quality begins long before the first part is produced.
Before a project enters the production phase, we analyze what is important, what could go wrong, how we will prevent those issues, and how we will control the process.
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full text
We analyze requirements → plan the process → anticipate risks → plan measurements → launch production → verify process capability → approve → produce in series → monitor → identify each batch → respond to deviations.
APQP · CTQ · PFMEA · Control Plan · MSA · SPC · Cp/Cpk · PPAP · Traceability
CTQ and requirements
from part function to process plan
Metrology
measurements tailored to characteristics and tolerances
Validation
First-Off · FAI · PPAP · Cp/Cpk
Process monitoring
SPC and proactive response to prevent nonconformities
Traceability
complete production batch history
Cleanliness and protection
cleaning · packaging · batch release
From requirements analysis to stable series production
We conduct the production ramp-up process in accordance with APQP principles as applicable to a contract manufacturer
01. We start by understanding what needs to be done
We begin every new project by analyzing the customer’s documentation and determining the requirements for the finished part. We identify which of these have the greatest impact on the function and quality of the finished product.
We check, among other things:
material,
dimensional and geometric tolerances,
functional surfaces,
threads, grooves, radii, and undercuts,
surface roughness requirements,
cleanliness requirements,
inspection and documentation requirements,
identification and packaging methods.
We pay special attention to features that are critical to the product’s performance.
Process and inspection planning begins with these characteristics.
02. We examine what could go wrong
We know from experience that a good process should prevent problems, not just detect them once they occur.
That is why, before launching production, we analyze the risks associated with each operation.
We take into account, among other things, the possibility of dimensional nonconformities, tool wear, use of the wrong material, measurement errors, batch mix-ups, improper protection of the finished product, and many other situations that may occur during the production process.
For significant risks, we define preventive actions and response procedures.
PFMEA – Process Failure Mode and Effects Analysis
All of this is done to reduce the number of situations in which a problem arises and to know exactly what to do when it does occur.
03. Every important characteristic has its own inspection method
Not all dimensions are inspected in the same way. A robust process requires an individual approach to inspection and measurement.
For each critical characteristic, we define:
We document these rules in the process Control Plan.
This ensures that inspection does not depend on the operator’s memory. It is part of a predefined process.
In rare cases, we may also implement 100% inspection if a customer requirement or risk analysis justifies such a solution. However, it is important to remember that this increases process costs and, given the very high stability of our processes, is generally not justified.
Complete text record
what we measure → what we use to measure it → when we measure → how often we measure → what constitutes an acceptable result → what we do in case of a deviation
04. First, we check the measurement itself. Only then do we examine the part.
Simply having an accurate measuring device is not enough.
We must also know whether the selected method actually allows us to reliably control a given characteristic. This refers not only to the accuracy of the instrument’s readings, but also to operator influence, the repeatability of results, and many other factors.
Therefore:
we select the measurement method based on the characteristic and tolerances,
we use reference standards,
we verify the repeatability of the measurement system,
we monitor the equipment,
for critical characteristics, we perform the required measurement system analyses.
MSA
–
Measurement System Analysis
Gage R&R
/
GRR
Before we measure something and make a decision based on the result, we want to know in advance whether that result can be trusted.
MEASUREMENT
Metrology tailored to turned parts with diameters of Ø1–12 mm
The SABNER laboratory uses several complementary measurement methods. The choice of equipment depends on the type of feature being inspected, the required accuracy, and the measurement point in the process.
VICIVISION MTL X5
When you need to quickly inspect an entire turned part
The MTL X5 is our primary system for the rapid, automated inspection of the geometry of small turned parts.
In a single measurement program, we can inspect multiple external features, including:
diameters,
lengths,
angles,
radii,
chamfers,
profiles,
thread geometry.
Automated measurement allows the same method to be used during process launch and subsequent series-production inspection. Its key advantage is eliminating operator influence on measurement results, and in many projects it is sufficient for all required measurements.
Mahr MarSurf CD 140
When you need to accurately measure the actual contour
Not every feature can be properly assessed based on an image from the MTL X5. This mainly concerns resolution and measurement precision, as well as measurements inside holes.
We use the MarSurf CD 140 for highly accurate analysis of part contours, including:
small radii,
chamfers,
grooves,
undercuts,
contour measurement in holes
selected surface parameters such as roughness
The system complements optical measurement where the precise contour profile is critical.
Mahr MarForm MMQ 200
When the dimension alone doesn’t tell the whole story about a part
Two diameters may fall within tolerance, yet the part may still not function properly.
The problem may lie in its form or in the relative position of its surfaces.
That is why we use the MMQ 200 to inspect features such as:
roundness,
cylindricity,
runout,
coaxiality,
straightness.
This is particularly important for mating surfaces, sealing surfaces, and components in which several diameters must maintain a specific relative position.
KEYENCE VR-5200
When we need to view a microcomponent in 3D
We use the KEYENCE VR-5200 for non-contact, precise analysis of surface geometry and topography in three dimensions.
The system allows for the analysis of, among other things:
profiles,
steps,
heights,
surfaces,
level differences,
features that are difficult to assess using conventional one-dimensional measurement.
The metrological precision of this system enables highly accurate measurements of geometric features that are difficult to measure with other instruments.
In-Process Inspection
Some measurements must be performed directly during the production process so that the operator can quickly assess its current status.
Mahr Pneumatic Measurement Systems
For specific critical dimensions with very tight tolerances, we use pneumatic measurements.
The instrument is configured for a specific feature and allows for the rapid detection of very small dimensional changes.
This solution is particularly useful for process control during series production.
GO / NO-GO Gauges
For rapid inspection of selected features, we use dedicated gauges:
ring gauges
pin gauges
They allow us to confirm, in a simple and repeatable manner, whether the inspected feature falls within the required range, directly on the production line without the need for a laboratory.
Reference Standards
For the ongoing monitoring of measurement systems, we use:
reference rings,
reference pins,
gauge blocks,
dedicated masters for specific instruments.
We perform some of the routine equipment inspections internally at short intervals. Periodic reference calibrations are carried out at external laboratories accredited by the PCA.
Controlled Measurement Conditions
Precise measurement requires stable conditions.
We conduct reference measurements in an air-conditioned metrology laboratory, under controlled conditions and at a reference temperature of 20°C.
Before particularly precise measurements, the workpiece and equipment are allowed time to reach thermal equilibrium.
05. A Good First Part Is Not Enough
The first parts produced serve to confirm the correctness of the prepared process; however, they are not proof that production will be stable and repeatable.
Therefore, during the launch of every new process, we examine the behavior of the monitored characteristics on a defined sample. Statistical analyses allow us to assess their variation, position within the tolerance field, and available safety margin.
Depending on the project requirements, we perform:
First-Off inspection,
FAI – First Article Inspection,
measurement system analyses MSA ,
process capability analyses,
Cp/Cpk studies,
Pp/Ppk studies.
We want to know not only whether the part is good, but also how much leeway our process has within the tolerance limits.
06. We Approve the Process Before Series Production
For projects requiring formal validation, we prepare the agreed-upon process approval documentation.
This may include, among other things:
PFMEA ,
MSA ,
measurement results,
process capability analyses,
material documentation,
production samples,
PSW .
For projects that require it, we prepare PPAP Level 3.
The scope of the documentation is always determined based on customer requirements and the nature of the project.
Only an approved and validated process proceeds to controlled series production.
07. Series Production Does Not Mean the End of Quality Control
Once full series production begins, we do not stop monitoring the process.
On the contrary – each subsequent batch provides data on how the process behaves over time.
We collect inspection results in our ERP system. The data is assigned to the project and production batch, allowing us to analyze the process history and generate the required reports.
We do not wait for a defect to occur – we monitor changes taking place during production and respond to signs of emerging deviations.
If a dimension begins to drift toward the tolerance limit, we want to identify this trend before the first nonconforming part appears.
One of the tools we use for this purpose is SPC – Statistical Process Control
We also use the collected measurement data for ongoing evaluation of process capability, applying metrics such as Cp/Cpk
All of these activities are intended to keep the production process fully capable of producing only conforming parts throughout the entire production period.
08. Every batch has its own history
When we produce thousands or millions of parts, we need to know what a specific batch was made of, when it was produced, and through which process.
This is critical in the event of a complaint that may be received later.
Therefore, production data forms a linked chain of information:
This is Traceability – the ability to link a specific batch number to the data generated during its production.
melt number
full text record
material batch / melt number
↓
EN 10204 3.1 inspection certificate
↓
production order
↓
production batch number
↓
process performed: machine + program + operator
↓
inspection results and process data
↓
cleaning
↓
packaging and labeling
↓
shipping batch
↓
customer
09. A part must not only be geometrically and dimensionally compliant; it must also be clean.
After machining, oil, fine process contaminants, and process residues may remain on the part’s surface – this is unavoidable in machining technology.
That is why finished parts at our company always undergo a cleaning process in the Dürr Ecoclean Compact 80C industrial system.
This process combines solvent cleaning with ultrasonics and vacuum operation, effectively degreasing even complex parts with small holes, channels, grooves, and hard-to-reach surfaces. The vacuum facilitates thorough evacuation of these spaces and residue-free final drying, while continuous distillation and filtration of the solvent maintain high and consistent process efficiency.
The required level of cleanliness depends on the part’s application; therefore, we establish technical cleanliness criteria for each specific project in collaboration with the customer.
If formal confirmation of the cleanliness level is required, appropriate testing can be performed at a specialized external laboratory.
10. We Protect Parts Even After Production
Finished parts can also be damaged or contaminated between the cleaning system and the customer’s warehouse.
To prevent this, we pay special attention to ensuring they are properly protected.
Depending on the geometry, surface, and customer requirements, we use, among other things:
vacuum packaging,
batch identification and labeling,
protective inserts and fillers that prevent parts from moving,
appropriately selected bulk packaging and cartons.
We agree the packaging method with the customer before series production begins and always recommend an appropriate solution.
11. If something goes wrong, we’re prepared.
In manufacturing practice, there is no time for improvisation when a nonconformity is detected. We prepare for this before production starts by planning the appropriate sequence of actions.
Depending on the situation, these steps include:
halting the process → identifying the batch → segregating material → analyzing the cause → correcting the process → re-inspection → deciding whether to resume production
For problems requiring formal analysis, we use the 8D – Eight Disciplines.
The results of the analysis may lead to updates to the PFMEA , Control Plan , process instructions, or inspection method.
In this way, the knowledge gained during production feeds back into the quality system, strengthening our expertise and the stability of future processes.
Quality is a system, not just a final inspection
The entire process can be summarized in a single sequence:
complete written record
Customer documentation
↓
Requirements analysis – CTQ
↓
Risk analysis – PFMEA
↓
Process and inspection plan – Process Flow + Control Plan
↓
Measurement validation – MSA / GRR
↓
Start-up – First-Off / FAI
↓
Process capability – Cp / Cpk / Pp / Ppk
↓
Approval – PPAP
↓
Series production
↓
SPC + Control Plan + Traceability
↓
Cleaning + packaging
↓
Batch release
We don’t want to check at the end whether we’ve managed to produce a good part.
We build the process so that a good part is its repeatable outcome.
The result of the process comes from combining planning, validation, series-production control, and Traceability.
1. Quality Planning
CTQ · PFMEA · Control Plan
2. Validation and Measurement
3. Series Production Control
4. Batch Finalization
Cleaning · Packaging · Batch Release
ISO 9001 and ISO 14001
Management systems support a controlled approach to process execution, production repeatability, documentation oversight, and responsible environmental management.
9001
PN-EN ISO 9001:2015
The certified scope covers the production of precision metal parts on CNC automatic lathes.
Download the ISO 9001 certificate14001
ISO 14001
SABNER operates in accordance with the ISO 14001 environmental management system, which complements the systematic approach to managing and improving processes.
Download the ISO 14001 certificateSABNER Quality Glossary
APQP – Advanced Product Quality Planning
A structured approach to preparing a new project for series production.
At SABNER, we apply APQP in the areas for which a contract manufacturer is responsible: requirements analysis, production process preparation, risk analysis, Control Plan, process validation, and the launch of series production.
The product is designed by the customer. We design and validate the manufacturing process.
CTQ – Critical to Quality
Characteristics that are particularly important for the quality or function of the product.
These may include, for example, a very precise diameter, concentricity, sealing surface, or a specific surface roughness.
CTQs are designated as such and receive special attention during process planning and inspection.
Process Flow Diagram – PFD
A map of the production process.
It shows, in sequence, all the relevant operations a part undergoes – from raw material to the finished and packaged part.
PFMEA – Process Failure Mode and Effects Analysis
A process risk analysis.
For each operation, we ask: what could go wrong, what might be the consequence, why might it happen, and how can we reduce the risk.
Control Plan
Process control plan.
It specifies what we control, by what method, how often, and what to do when the result does not meet the established criteria.
Reaction Plan
Deviation response plan.
It specifies the actions to be taken by the operator and the organization when a measurement or process begins to fall outside established limits.
MSA – Measurement System Analysis
Measurement system analysis.
We verify whether the measurement method is sufficiently reliable to serve as the basis for decisions regarding product quality.
Gage R&R / GRR – Gauge Repeatability and Reproducibility
One of the MSA analyses.
It shows what portion of the variation in the result stems from the measurement system itself, the instrument, or the measurement method.
SPC – Statistical Process Control
Statistical process control.
Instead of looking solely at a single result, we observe the process’s behavior over time. This allows us to identify a trend or change before it leads to the production of nonconforming parts.
Cp and Cpk
Process capability indices.
They show how process variation relates to the available tolerance and how well the process is centered within the tolerance range.
The greater the process’s safety margin relative to the tolerance limits, the greater its capability.
Pp and Ppk
Indicators describing process performance based on observed data.
Like Cp and Cpk, they help assess the relationship between process variability and tolerance, but are used in a different statistical context and under different assumptions regarding the data.
FAI – First Article Inspection
An inspection of the first parts produced in a process being launched.
Its purpose is to confirm that the prepared process is capable of producing a part in accordance with the documentation.
PPAP – Production Part Approval Process
A formal process for approving parts and the production process before the start or full launch of series production.
The PPAP package may include, among other things, a PFMEA, Control Plan, MSA, dimensional results, capability analyses, and material documentation.
PSW – Part Submission Warrant
A document summarizing the submission of a part in the PPAP process.
It confirms basic information about the product, the process, and the approval package submitted to the customer.
Traceability – traceability
The ability to trace the history of a specific batch.
It links the material, documentation, production batch, actual process flow, inspection results, cleaning, packaging, and shipping.
GO / NO-GO
A quick inspection method using a gauge.
The “GO” side must match the correct part, while the “NO-GO” side should not pass. This provides the operator with a simple pass/fail decision.
100% Inspection
Inspection of a specific characteristic on every part produced.
We use this method in selected cases when required by the customer or based on a process risk analysis. Since it increases the scope of inspection operations, it also affects production costs.
8D – Eight Disciplines
A structured method for solving quality problems.
It guides the process from protecting the customer and identifying the problem, through root-cause analysis and corrective actions, to confirming their effectiveness.
EN 10204 3.1
An EN 10204 type 3.1 inspection certificate issued by the material manufacturer.
It allows a specific batch of material to be linked to test results and constitutes one of the elements of production traceability.
Do you have a project for series production?
Send us the drawing and basic quality requirements.
We will analyze feasibility, critical features, inspection methods, the required scope of documentation, cleanliness, packaging, and process startup conditions.
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