A crankshaft is long, sensitive to imbalance and has hard-to-reach bores — and that is exactly where oil, cooling lubricant and chips from machining sit.
Cleaning crankshafts
1 · The challenge
Why crankshafts are difficult to clean
Crankshafts are long and sensitive to imbalance, and with main bearing, crankpin bearing and oil bores they carry bores and hard-to-reach areas. These are three properties that arrive at three different places: the overall length at the dimensions of the system, the sensitivity at the handling, the bores at the method.
What has to be removed from a crankshaft comes from machining: in particular oil and cooling lubricant, plus chips and particles. So it is not only an outer surface that has to be cleaned — the task includes making the bores and the hard-to-reach areas accessible for cleaning and rinsing in the first place.
A long component that is sensitive to imbalance cannot be held just any way. On the crankshaft, the workpiece fixture has to be safe and reproducible: safe so that the part passes through the process unharmed, and reproducible so that every part lies in the same place and every result remains comparable.
The task does not end with cleaning. The process medium has to drain out of the bores again, and what does not drain has to be removed by the drying. On the crankshaft, drainage and drying are therefore part of the system design and not its appendix — and they depend on the position in which the component passes through the process.
2 · Engineering considerations
What we base the system design on
- 01
Part geometry
Crankshafts are long and geometrically demanding components. The overall length acts on the dimensions of the system, on the fixture and on how the part is moved through the process; the sensitivity to imbalance is added as a requirement of its own on the handling. - 02
Internal geometry
Main bearing, crankpin bearing and oil bores are the hard-to-reach areas on the crankshaft. For them it has to be clarified not only how the cleaning medium gets there, but also how rinsing is done and how the process medium comes out again. - 03
Type of contamination
On the crankshaft, contamination from machining has to be removed, in particular oil and cooling lubricant, plus chips and particles. Which method comes into question depends on this contamination and on its position in the component — not on the name of the component. - 04
Workpiece fixture
The fixture of a crankshaft has to be safe and reproducible. On a long component that is sensitive to imbalance, it is not an accessory but the point at which it is decided whether every part has the same position in the process — and thus whether the result depends on the part or on chance. - 05
Part orientation
How the crankshaft lies in the system helps decide accessibility, drainage and drying. The component orientation is not simply adopted from the customer, but analyzed by us as part of the process design — according to nozzle accessibility, spray shadow, drainage of the process medium and the prerequisites for drying. There is no position that is better across the board; it is determined component- and process-specifically. - 06
Drying
What process medium remains in a bore is not dealt with by the cleaning. On the crankshaft, drainage of the process medium and drying belong to the task; how elaborate they become depends on the accessibility of the bores and on the position in which the part passes through the process.
3 · The system concepts
Which system concepts come into question
Special-purpose systems
If no standard machine type solves the task — because of the part size, the geometry, the contamination or the process environment — a special-purpose system comes into question. Systems for crankshafts we have built; the system size follows from part dimensions, weight, production volume and process requirements and is determined project-specifically.
Rotary indexing cleaning systems
RTIf the process can be broken down into fixed stations and loading and unloading are to take place while cleaning, rinsing and drying run at the stations, a rotary indexing cleaning system can be a possible concept. The process steps are then distributed over stations instead of one chamber.
Continuous cleaning systems
ZDDepending on the process, a continuous cleaning system can be relevant as well — namely when the cleaning is integrated into a production line and the parts are to pass through instead of waiting as a batch.
Drying
How the process medium comes out of the bores again is a design matter of its own — recirculated air, infrared drying, air blow-off or vacuum drying, depending on the drying requirement and designed to suit the project.
The principle
Why there is no prescribed machine for the crankshaft
A component name is not a system decision. That a crankshaft is long, sensitive to imbalance and bored inside says which questions have to be clarified — not which machine type stands at the end. Which concept fits arises from contamination, residual contamination requirement, production volume, cycle time, material flow and degree of automation together. There is no rule “crankshaft, therefore system Y”. What you see here is the consideration, not its result.
4 · What else to consider
What else has to be clarified beyond cleaning
- 01
Systems for crankshafts we have built
Crankshafts are among the tasks for which we have built systems — alongside washing out salt cores and systems for marine engines. What follows from that is not a machine type assignment, but experience with the task: the system size follows from part dimensions, weight, production volume and process requirements. - 02
The fixture is designed with the process, not after it
Holding a long component safely and reproducibly means that fixture and process are created together: the position determines where the process medium gets to, where it drains and what the drying still has to do. Whoever designs the fixture last has already answered the three questions without having asked them. - 03
Drainage and drying come at the end and are decided at the beginning
Whether the process medium comes out of an oil bore again is not a question of the last station, but of the orientation of the component and the accessibility of its bores. Both are defined in the process design — at the same place as the residual contamination requirement.
Questions and answers
Frequently asked questions about cleaning crankshafts
How are crankshafts cleaned?
Which system comes into question for crankshafts?
Which contamination sits on a crankshaft?
Why is the workpiece fixture so important for crankshafts?
Direct contact
Hauptstraße 31
93186 Pettendorf
Pettendorf bei Regensburg
Fax +49 (0) 9409-777 3607
Technically responsible for this page: Günther Zippel — International Sales & Technical Consulting