The spray jet hits what it sees — and what it does not see only becomes visible in the residual contamination verification.
Cleaning cylinder heads
1 · The challenge
Why cylinder heads are difficult to clean
On the cylinder head, the contamination sits where the spray jet does not reach: in internally branched channels, cross-drilled holes and blind holes. The spray jet hits what it sees — and what it does not see only becomes visible in the residual contamination verification.
Engine blocks and cylinder heads are thus the most demanding cleaning parts in automotive production — not because of their size, but because of their internal structure. Coolant and oil channels, blind holes, through-holes and threads run through the entire component. A spray jet hits the outer surface; it does not reach the end of a deep bore.
What sits in these channels — chips, oil, emulsion, a burr — sits at a place that cannot be reached easily. A burr that remains on the cylinder head is not a form deviation: it comes loose later and travels to where the component works. A detached burr in the channel is thus residual contamination.
In deburring, a second characteristic is added on the cylinder head: many bores, many bore intersections, and the parts are heavy. Deburred by hand, every result is a different one — what works on a test part does not carry a production run.
2 · Engineering considerations
What we base the system design on
- 01
Part geometry
Cylinder heads and engine blocks are large and heavy; with commercial vehicle components, larger dimensions and higher weights are added. Both act on chamber and zone sizes, payload and loading — which is why we calculate a commercial vehicle component separately instead of transferring an existing system design. - 02
Internal geometry
Coolant and oil channels, blind holes and through-holes decide the method on the cylinder head: spraying creates a spray shadow, not every surface can be reached. Where spraying ends at the spray shadow, immersion and flooding lead to the result; many bores additionally speak for lance technology — targeted instead of across the whole surface. - 03
Workpiece fixture
The workpiece fixture helps decide the result on the cylinder head because the lance has to find the bore — and at the same place on every part. The parts carrier is therefore not an accessory but an essential part of the system concept. - 04
Residual contamination requirement
What has to be verified on the cylinder head stands at the beginning of the system design, not at its end: what is required are residual contamination values, technical cleanliness and — depending on the downstream process — suitability for the next production step. The required values act on the method, the filtration, the drying and the workpiece fixture at the same time. - 05
Deburring requirement
Whether the cylinder head additionally has to be deburred is decided in the same technical clarification: where a burr is involved as well, water jet deburring is usually the better solution. The burr root at the bore intersection of two bores lies where no tool reaches mechanically. - 06
Production volume
Small to medium production volumes speak rather for a chamber cleaning system on the cylinder head, high production volumes rather for a continuous cleaning system. The machine type thus follows the production, not the component. - 07
Cycle time
In engine production, the line runs in cycles of seconds — there, cleaning the cylinder head is not a process of its own but a step between two others, and it has to follow the cycle of the line, not the other way round. It is the order of magnitude that decides, not the number of seconds: if several minutes per cycle are permissible, the chamber cleaning system comes into question; if production demands cycles in the order of seconds, rather the continuous cleaning system.
3 · The system concepts
Which system concepts and methods come into question
Chamber cleaning systems
ZKFor cylinder heads and engine blocks, the chamber cleaning system can make sense when changing, also more complex workpieces run in small to medium production volumes and several minutes per cycle are permissible. Large components such as engine blocks we clean in it with lance technology.
Continuous cleaning systems
ZDIf the engine line demands cycles in the range of seconds and a continuous flow, the continuous cleaning system comes into question in particular for cylinder head and engine block — the same component, another viable concept.
Rotary indexing cleaning systems
If it is not the cleaning performance that stands in the way on the cylinder head, but loading and unloading, the rotary indexing cleaning system can make sense: the process is broken down into fixed stations, loading and unloading take place at a single position. That presupposes a defined production process with a constant process sequence.
Robot cell
If the cylinder head has to be moved between cleaning, rinsing, drying and a subsequent test station, the robot cell comes into question — the robot then takes over the handling between the stages. We have built a cleaning cell with robot handling for aluminum cylinder heads.
Immersion cleaning systems
Where spraying ends at the spray shadow on the cylinder head, immersion can lead to the result: the component is brought completely into the process medium instead of only being hit from the outside.
Flood washing
In flooding, the process medium is guided over and around the cylinder head with volume instead of pressure. That comes into question in particular when channels and blind holes cannot be reached by the spray jet.
Lance technology
If a single bore on the cylinder head has to be hit precisely, lance technology is added — then it is not the whole system that works harder, but one nozzle at the right place.
Water jet deburring
If a burr root sits at the bore intersection of two bores on the cylinder head, water jet deburring comes into question: the water jet needs no path for a tool, only one for the process medium.
The principle
Why several solutions are possible for the cylinder head
None of these assignments is a rule. Engine blocks, for example, can be cleaned in a chamber cleaning system with lance technology just as well as in a continuous cleaning system — the same component, two viable concepts. The same applies to the cylinder head: depending on production volume, cycle time, residual contamination requirement and material flow, it can be better placed in a different system — there is no rule “component X, machine Y”. What you see here is the consideration, not its result.
4 · What else to consider
What else has to be clarified for the cylinder head beyond cleaning
- 01
Burr and residual contamination are two sides of the same task
A burr that remains in the channel of the cylinder head is not a form deviation but residual contamination. Whoever treats the burr as a deburring topic and the residual contamination value as a cleaning topic separates two sides of the same task — which is why we consider both together. - 02
In deburring, reproducibility counts, not speed
When deburring the cylinder head, reproducibility is the actual argument: a programmed sequence does the same on part one thousand as on part one. Whether this becomes a robot with the component, a robot with the nozzle or a stationary deburring machine is then decided by the cycle. - 03
The verification is part of the task
On the cylinder head it is not enough for the part to look clean. What is required are residual contamination values, technical cleanliness and — depending on the downstream process — suitability for the next production step.
Questions and answers
Frequently asked questions about the cylinder head
Why are cylinder heads hard to clean?
Which system comes into question for cylinder heads?
Why is a burr on the cylinder head a cleaning topic?
Why is the workpiece fixture so important on the cylinder head?
Why can a cylinder head not be deburred by hand?
Direct contact
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Pettendorf bei Regensburg
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Technically responsible for this page: Günther Zippel — International Sales & Technical Consulting