Plastic Plunger Blocks & Dosing Pistons

Plastic Plunger Blocks & Dosing Pistons for Filling, Metering & Pump Systems

Kaybin manufactures custom plastic plunger blocks and plastic dosing pistons for filling machines, metering pumps, volumetric cylinders and packaging systems where controlled displacement, dimensional stability and chemical resistance are critical. Components are precision-machined to drawing, CAD file or sample for OEM production and industrial replacement applications across South Africa and Africa.

This page covers industrial plastic plunger blocks, reciprocating pistons and dosing piston assemblies only — not rubber plungers, medical syringe components or consumer hardware.

Applications & Equipment Coverage

Plastic plunger blocks and pistons are commonly used in:

• Liquid filling machines
• Volumetric dosing and batching systems
• Chemical metering pumps
• Bottling and capping lines
• Syrup and viscous product fillers
• Transfer and dispensing skids
• Custom OEM packaging machinery

Primary functional roles include:

• Displacing a fixed volume per stroke
• Maintaining concentric reciprocating movement inside a dosing cylinder
• Supporting dynamic seals (O-rings, U-seals, cup seals)
• Providing a low-friction sliding surface against bore or liner
• Maintaining stroke repeatability and dosing accuracy

Piston vs Plunger – Industrial Context

In filling and dosing systems, the terms "plunger" and "piston" are often used interchangeably. A plunger block may refer to the machined drive component mounted to an actuator rod, while a piston typically refers to the displacement element operating inside the cylinder bore. Many OEM systems combine both functions into a single plastic piston assembly. Kaybin manufactures both plunger-style blocks and precision plastic dosing pistons.

Material Options & Engineering Behaviour

Materials are selected based on media compatibility, dimensional stability, pressure conditions and seal interface requirements.

• PTFE (Virgin & Filled Grades)
  Very low friction and high chemical resistance. Filled grades improve wear resistance and reduce creep compared to virgin PTFE.
• Acetal / POM (Delrin-type)
  Excellent dimensional stability and low moisture absorption. Suitable for tight-tolerance volumetric pistons and consistent dosing accuracy.
• Nylon (PA6 / PA66 / Filled Grades)
  Tough and impact-resistant for mechanical piston drives. Moisture absorption considered in clearance design.
• UHMWPE
  Low friction and abrasion resistance for lower-pressure reciprocating applications.