Seal Manufacturing Technology

Ing. Jan Ondra

26. 9. 2024

Comparison of Seal Manufacturing Technologies for Hydraulics

Sealing elements used in hydraulic cylinders are manufactured using two primary technologies. These are:

  1. Injection Molding Technology (Injection Molding)
  2. CNC Turning Technology (CNC Turning)

Each of these technologies has its advantages and disadvantages and is suitable for different situations. A comparison of both technologies can be found below. More information about our production capabilities can be found here.

Injection Molding Technology

Process:

  • Injection of plastic or elastomer into a mold under high pressure, where the material hardens.
  • Primarily used for thermoplastics and elastomers.

Advantages:

  • High-volume production: The technology is suitable for manufacturing large series with a low unit cost.
  • Repeatability: Each piece produced by injection molding has consistent dimensions and quality.
  • Complex shapes possible: The injection mold allows for the production of seals with very complex geometries.
  • Production speed: Once the mold is created, a large number of pieces can be produced quickly.

Disadvantages:

  • Initial costs: High costs for manufacturing injection molds, which can be uneconomical for small series.
  • Mold accuracy demands: Any design change requires modification or a new mold, which can be time-consuming and costly.

CNC Turning Technology

Process:

  • Seals are manufactured by removing material from a blank using a computer-controlled CNC lathe.

Advantages:

  • Flexibility: CNC technology allows for rapid adaptation to design changes without the need to produce new molds.
  • High precision: CNC machines achieve very high precision and are ideal for manufacturing seals with tight tolerances.
  • Suitable for small series and prototypes: Production costs are not quantity-dependent, making this method suitable for small series or one-off orders.
  • Wide range of materials: CNC turning allows for working with various materials, including metals and special plastics.

Disadvantages:

  • Slower production: The process is more time-consuming compared to injection molding.
  • Higher unit costs: For large series, the cost per piece can be higher than with injection molding.
  • Less complex shapes: Turning is more suitable for simpler geometries, while more complex shapes may be more difficult to achieve.

Seal Manufacturing Technology

  • Injection molding is more advantageous for high-volume production of seals with complex shapes and requirements for low unit cost. It is suitable for long-term projects where initial mold costs are justified.
  • CNC turning is ideal for small series, prototypes, or applications requiring high precision and rapid design modifiability.
FactorInjection MoldingCNC Turning
Suitability for Series ProductionHigh (for large volumes)High (for small volumes)
Initial InvestmentHigh (tools, molds)Low (machine setup)
Unit CostLow for large seriesHigher, especially for large series
Design AdaptabilityLow (requires new molds)High (software modification)
PrecisionHigh, but dependent on mold qualityVery high, independent of geometry
Production TimeShort (after mold production)Longer (more time-consuming)
Complexity of ShapesHighMore limited (simpler geometries)
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