The burr root sits at the bore intersection of two bores — no tool gets there, not because it would be too big, but because no path leads to it.
Cleaning and deburring valve blocks
1 · The challenge
Why valve blocks are difficult to deburr and to clean
Two bores meet inside the valve block, and exactly at the bore intersection sits the burr root. No tool gets there — not because it would be too big, but because no path leads to it.
A valve block is at its core nothing other than a block of material with a channel system inside: cross bores and cross-drilled holes that intersect several times. At every bore intersection a burr forms, and no mechanical tool reaches any of them.
Added to this on the valve block are tight tolerance positions on the sealing faces: the burr may be removed, the edge must not be changed. How clean these faces are only becomes apparent in the downstream process — in adhesive bonding, coating or sealing.
A burr that remains on the valve block rarely stays a form deviation. It comes loose later and travels to where the component works — into oil and hydraulic channels, to valves, into pumps and gearboxes. A detached burr in the channel is thus not only a deburring problem but a residual contamination problem.
The same geometry makes cleaning the valve block difficult as well. Blind holes and branching channels are exactly the places a spray jet does not reach: it hits what it sees. What it does not see stays untreated — and becomes visible in the residual contamination verification.
2 · Engineering considerations
What we base the system design on
- 01
Part geometry
Valve blocks are predominantly made of aluminum and aluminum die casting — a material that machines easily and breaks away in a ductile manner. The material is still no limit; it is the focus because the components are manufactured that way, not because the method would be restricted to it. What is decisive are part geometry, burr root, accessibility and process objective. - 02
Internal geometry
On the valve block, blind holes, through-holes and internal channels with cross-drilled holes decide the method: spraying creates a spray shadow, not every surface can be reached. Many bores additionally speak for lance technology — targeted instead of across the whole surface. - 03
Workpiece fixture
On the valve block, the parts carrier is not an accessory but an essential part of the system concept: its design engineering helps determine where spray shadow arises and whether the nozzles reach the component. In deburring, a jet works against the component — the clamping fixture has to absorb this force and at the same time leave every deburring location freely accessible. That is why it is a design component of the process. - 04
Residual contamination requirement
What has to be verified on the valve block stands at the beginning of the system design, not at its end: the required residual contamination values act on the method, the filtration, the drying and the workpiece fixture at the same time. The measure for it is not the appearance, but the function — what stays in the channel stays in the system. - 05
Deburring requirement
Whether the valve block 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. Four of the seven burr types we list sit at or in bores — there is no fixed standard burr type; the part geometry is what governs. - 06
Production volume
If the valve block is deburred by hand, that works as long as the production volume is small and nobody demands a verification. As soon as one of the two tips, quality hangs on the form of the day and the cycle on the number of hands. - 07
Cycle time
On the valve block, too, 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. Where the cycle is measured in seconds and the system stands in a line, it is continuous or rotary indexing cleaning systems. - 08
Downstream process
Whether the valve block is adhesively bonded, coated or painted after cleaning changes the requirement fundamentally — right down to the question of which water quality is needed. That shows first on the sealing faces.
3 · The system concepts
Which system concepts and methods come into question
Water jet deburring
If the burr root on the valve block sits at the bore intersection of two bores, water jet deburring comes into question: the water jet needs no path for a tool, only one for the process medium.
Robot cell with a single robot
If different valve blocks run in small to medium production runs, the single-robot cell can make sense: it guides the nozzle to every deburring location, including cross-drilled holes and internal channels — exactly where a fixed fixture no longer fits the next component.
Robot cell with two robots
If a valve block has many deburring locations and they are distributed, the dual-robot cell comes into question in particular — not because the jet would be too slow, but because there are many locations and the work can be divided.
Stationary deburring system
If nothing changes on the valve block — not the component, not the position, not the deburring locations — a fixed nozzle system can be enough: even without movable jet guidance, the jet reaches burrs at and in bores; the nozzle only has to stand right once.
Chamber cleaning systems
ZKFor valve blocks, the chamber cleaning system can make sense when a changing range of parts runs and several process steps are to take place in one closed chamber.
Continuous cleaning systems
ZDIf production on the valve block demands cycles in the order of seconds and a continuous flow in the line, the continuous cleaning system comes into question: successive zones instead of one chamber — the parts do not wait, they flow.
Rotary indexing cleaning systems
RTIf it is not the cleaning process on the valve block that is the bottleneck, but loading and unloading, the rotary indexing cleaning system can come into question: loading and unloading run parallel to processing, the auxiliary time drops out of the cycle. A defined production process with a constant process sequence is presupposed.
Immersion cleaning systems
ZTIf spraying on the valve block fails at the spray shadow, the immersion cleaning system can come into question: the component is immersed completely in the process medium so that the process medium reliably reaches all areas.
Lance technology
If a valve block has many bores and through-holes, lance technology can be added: the process medium is guided into the individual bore in a targeted way instead of across the component. Each lance has to match its bore and hit it reliably — the arrangement is part of the design engineering, not an accessory.
The principle
Why several solutions are possible for the valve block
None of these assignments is a rule. A valve block or hydraulic manifold is at its core the same case: a block of material with a channel system inside — manifolds, housings and valves follow the same geometry and cleanliness logic. That is why on the valve block, too, it is not the name of the component that decides, but the interplay of part geometry, production volume, cycle time, residual contamination requirement and material flow. 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 valve block beyond cleaning and deburring
- 01
It is not the size of the burr that decides
On the valve block, two other characteristics count: the burr root — how firmly the burr is attached to the component — and the accessibility — whether a tool or a jet reaches the place at all. A burr you can get to is a production task. A burr at a cross-bore intersection is a design task. - 02
The water jet removes the burr, it does not shape the edge
The tight tolerance positions on the sealing faces of the valve block are at the same time a limit of the method: the burr may be removed, the edge must not be changed. If a defined chamfer or radius is demanded at this place, another method is the right one — and we say so before the quotation, not at acceptance. - 03
It is two verifications, not one
The valve block is inspected twice: residual burr — is the burr gone? — and residual contamination — is the part clean? Both verifications run through one contact person, but not both through the same hands: the residual contamination analysis is carried out by an independent, accredited test laboratory, not by us. - 04
At the beginning stands the geometry, not the machine
A jet that misses the bore intersection in the valve block by a few degrees does not remove the burr. What is decisive is the alignment — and that is why we need 3D data before a machine concept is discussed. - 05
Deburring and cleaning are considered together
A burr in the channel of the valve block is not a form deviation, it is residual contamination as soon as it comes loose. That is why it is considered together whether deburring and cleaning take place — and whether both are possible in one step.
Questions and answers
Frequently asked questions about the valve block
Where does the burr sit on the valve block?
Does the size of the burr decide the method?
Can the water jet produce a chamfer on the sealing faces?
Why is the valve block a cleaning case as well?
Which system comes into question for valve blocks?
Direct contact
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Pettendorf bei Regensburg
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Technically responsible for this page: Günther Zippel — International Sales & Technical Consulting