Mechanical Components

Mechanical parts of an injection molding machine

Point at a number or a part of the drawing.

1. 1Clamping cylinder

   Hydraulic cylinder behind the rear platen. Its rod pushes the crosshead, which straightens the toggle to close the mold and folds it to open.

   Clamping Components (2)

2. 2Toggle links and crosshead

   Steel links between the rear and moving platens. Straightened, they lock the mold shut and multiply the cylinder’s force into the clamping force.

   Toggle Arm / Link RodToggle Link / CrossheadToggle & Links (5)

3. 3Toggle pins and bushings

   Hardened pins join the links; the bushings around them carry the load and wear first. Worn bushings show as play in the toggle and uneven clamping.

   Toggle Pin / Hinge PinToggle Link BushingToggle Pin BushingToggle Link Connecting Rod Bushing

4. 4Guide columns

   Hardened steel columns, with bushings and lock nuts, that guide a moving plate or crosshead so it stays square and in line as it travels. The same parts are used in the injection unit and the clamping unit.

   Bushings & Guides (8)

5. 5Tie bars and nuts

   Four steel bars that join the front and rear platens and carry the clamping force. The moving platen slides along them on bushings; the nuts set the mold height.

   Tie Bars & Columns (7)

6. 6Platens

   Heavy cast plates: the rear platen holds the toggle, the moving platen carries the moving mold half and the front (stationary) platen the fixed half.

   Platens (1)

7. 7Mold mounting

   The locating ring centres the mold on the front platen in line with the nozzle; clamping plates hold the mold halves on the platens.

   Mold Clamping Plate / Locating Ring

8. 8Barrel, screw and nozzle

   The screw turns inside the heated barrel to melt the plastic, then moves forward to inject it through the nozzle into the mold.

   Barrels & Cylinders (5)

9. 9Injection cylinder

   Hydraulic cylinder that drives the screw forward to inject and holds pressure while the part sets. Its seals are wear parts.

   Injection CylinderScrew Barrels & Seals (4)

10. 10Linear guide

    Rail and slider blocks under the injection unit. The unit slides on them when it moves the nozzle to and from the mold.

    Safety Guards (1)

11. 11Ejector

    Small cylinder on the back of the moving platen. Its rods push the mold’s ejector plate to free the part; return springs bring it back.

    Return Spring / Ejector SpringEnd Caps & Plates (2)

12. 12Machine feet

    Leveling bolts and anti-vibration pads under the frame. They set the machine level and reduce the vibration passed to the floor.

    Machine Leveling Foot BoltAnti-Vibration Foot Pad