---
title: "Mechanical Components"
url: "https://www.imspares.com/categories/mechanical/"
---

# Mechanical Components

Mechanical parts and assemblies including barrels, screws, tie bars, bushings, platens, and clamping components.

## Mechanical parts of an injection molding machine

1. **Clamping 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.
2. **Toggle 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. Part numbers: MC-TL-02, MC-CR-02.
3. **Toggle 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. Part numbers: MC-TL-03, MC-TL-05, MC-JM-02, MC-JM-05.
4. **Guide 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.
5. **Tie 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.
6. **Platens**: 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.
7. **Mold 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. Part numbers: MC-JM-04.
8. **Barrel, 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.
9. **Injection cylinder**: Hydraulic cylinder that drives the screw forward to inject and holds pressure while the part sets. Its seals are wear parts. Part numbers: MC-BC-06.
10. **Linear guide**: Rail and slider blocks under the injection unit. The unit slides on them when it moves the nozzle to and from the mold.
11. **Ejector**: 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. Part numbers: MC-SR-05.
12. **Machine feet**: Leveling bolts and anti-vibration pads under the frame. They set the machine level and reduce the vibration passed to the floor. Part numbers: MC-TL-01, MC-TL-07.

## Barrels & Cylinders

Bimetallic barrels, nitrided cylinders, and barrel assemblies

- [MC-BC-01 Bimetallic Barrel & Screw Assembly](https://www.imspares.com/parts/mc-bc-01/): High-quality bimetallic barrel and screw assembly for plastic injection molding machines.
- [MC-BC-02 Injection Screw](https://www.imspares.com/parts/mc-bc-02/): Replacement injection screw for injection molding machine plasticizing unit.
- [MC-BC-06 Injection Cylinder](https://www.imspares.com/parts/mc-bc-06/): Injection hydraulic cylinder for injection molding machine injection unit.
- [MC-BC-07 Injection Nozzle](https://www.imspares.com/parts/mc-bc-07/): Precision-machined injection nozzle for plastic injection molding machines.
- [MC-BC-08 Barrel Front Flange (Front Head)](https://www.imspares.com/parts/mc-bc-08/): Barrel front flange (front head) for Haitian MA series injection molding machines.

### Parts of the injection unit

1. **Nozzle**: Screws into the front of the barrel and seals against the mold’s sprue bushing. The melt passes through it on every shot. Part numbers: MC-BC-07.
2. **Barrel front flange**: Also called the front head or end cap. It closes the front of the barrel and holds the nozzle. Part numbers: MC-BC-08.
3. **Barrel**: Thick steel tube the screw turns in. Bimetallic barrels have a hard alloy lining that resists wear from glass-filled and abrasive plastics. Part numbers: MC-BC-01, MC-SB-01.
4. **Screw**: Melts and meters the plastic. Its flights are deep in the feed zone, get shallower through the compression zone and stay shallow in the metering zone. Part numbers: MC-BC-02.
5. **Screw tip and check ring**: A non-return valve on the front of the screw. The ring lets melt pass while the screw turns and seals when it injects, so the shot does not flow back.
6. **Heater bands**: Bands around the barrel and nozzle that heat the plastic to its processing temperature, each zone controlled by its own thermocouple.
7. **Hopper and feed throat**: Pellets drop from the hopper through the feed throat into the screw. The throat is usually water-cooled so the pellets do not melt and stick before the screw.
8. **Injection cylinder**: Hydraulic cylinder that drives the screw forward to inject and holds pressure while the part sets. Its seals are wear parts. Part numbers: MC-BC-06.

## Screw Barrels & Seals

Screw barrel assemblies, hydraulic cylinder seal sets and piston rod nuts

- [MC-SB-01 Screw Barrel Assembly](https://www.imspares.com/parts/mc-sb-01/): Complete screw and barrel assembly for injection molding machine plasticizing unit.
- [MC-SB-07 Piston Rod Seal Set](https://www.imspares.com/parts/mc-sb-07/): Piston rod seal set for injection molding machine hydraulic cylinders.
- [MC-SB-08 Hydraulic Cylinder Seals & Y-Ring](https://www.imspares.com/parts/mc-sb-08/): Hydraulic cylinder seal kits and Y-ring piston rod seals for injection molding machine cylinders.
- [MC-SB-10 Piston Rod Nut](https://www.imspares.com/parts/mc-sb-10/): Injection cylinder piston rod nut for Haitian and equivalent injection molding machines.

### Seals of a hydraulic cylinder

1. **Cylinder tube and end caps**: The honed tube and the end caps hold the oil. Oil pumped into one end or the other moves the piston.
2. **Piston rod nut**: Holds the piston on the threaded end of the rod. It must stay tight: a loose nut lets the piston knock and damages the seals. Part numbers: MC-SB-10.
3. **Piston**: Separates the two oil chambers of the cylinder. Pressure on one side pushes it, and the rod with it.
4. **Piston seals**: Y-rings and wear rings in the piston grooves. They keep oil from passing the piston; worn piston seals make the cylinder creep and lose force. Part numbers: MC-SB-08.
5. **Piston rod**: Chrome-plated rod that carries the force out of the cylinder. Scratches or pitting on its surface quickly destroy the rod seals. Part numbers: MC-GZ-01.
6. **Rod seal set**: Guide ring, rod seal and wiper in the front head. The seal holds the oil in, the wiper keeps dirt out and the guide ring keeps the rod centred. Part numbers: MC-SB-07.
7. **Screw barrel assembly**: The barrel and screw supplied together as a matched set, with the screw head, ready to fit to the injection unit. Part numbers: MC-SB-01.

## Tie Bars & Columns

Tie bars, toggle pins, and column assemblies

- [MC-TC-01 Tie Bar](https://www.imspares.com/parts/mc-tc-01/): High-strength tie bar for injection molding machine clamping unit.
- [MC-TC-03 Tie Bar Liner Bushing](https://www.imspares.com/parts/mc-tc-03/): Tie bar liner bushing for injection molding machine platen tie bar bores.
- [MC-TC-06 Tie Bar Nut](https://www.imspares.com/parts/mc-tc-06/): Tie bar nut (split nut) for injection molding machine clamping unit.
- [MC-TC-07 Tie Bar Bushing](https://www.imspares.com/parts/mc-tc-07/): Tie bar bronze bushing for injection molding machine platen guide bearings.
- [MC-TC-09 Tie Bar Adjustment Bushing](https://www.imspares.com/parts/mc-tc-09/): Tie bar adjustment bushing for injection molding machine clamping force adjustment.
- [MC-TC-13 Tie Bar End Cap / Lock Ring](https://www.imspares.com/parts/mc-tc-13/): Tie bar end cap and lock ring for injection molding machine clamping unit.
- [MC-TC-0102 Tie Bar Set (Pair)](https://www.imspares.com/parts/mc-tc-0102/): Matched pair of tie bars for injection molding machine clamping unit.

### Parts of the tie bar assembly

1. **Tie bar**: One of four steel bars that join the stationary and rear platens. The moving platen slides along them, and they stretch slightly as they carry the clamping force. Part numbers: MC-TC-01, MC-TC-0102.
2. **Adjustment bushing**: Part of the mold height adjustment behind the rear platen. Turning the adjusting nuts moves the rear platen along the tie bars to suit the mold thickness. Part numbers: MC-TC-09.
3. **Liner bushing**: Bronze sleeve lining a platen bore, so the platen slides on the tie bar without wearing the bar or the bore. Part numbers: MC-TC-03.
4. **Tie bar bushing**: Flanged bushing in each bore of the moving platen. It guides the platen along the tie bar and keeps it square as the mold opens and closes. Part numbers: MC-TC-07.
5. **Tie bar nut**: Threaded nut on the tie bar end that holds the bar in the stationary platen and takes the clamping load. Part numbers: MC-TC-06.
6. **End cap and lock ring**: Covers the tie bar end and locks the nut, so the tie bar stays in place in the stationary platen. Part numbers: MC-TC-13.

## Bushings & Guides

Guide bushings, slide bushings, and linear guides

- [MC-GZ-01 Injection Piston Rod](https://www.imspares.com/parts/mc-gz-01/): Injection unit piston rod for injection molding machine injection cylinder.
- [MC-GZ-02 Guide Column Nut (Type 2)](https://www.imspares.com/parts/mc-gz-02/): Guide column lock nut for injection molding machine clamping unit guide columns.
- [MC-GZ-03 Guide Column Nut (Type 3)](https://www.imspares.com/parts/mc-gz-03/): Guide column flanged nut for injection molding machine clamping unit.
- [MC-GZ-04 Locking Nut / Jam Nut](https://www.imspares.com/parts/mc-gz-04/): Locking jam nut for injection molding machine guide columns and shafts.
- [MC-GZ-5 Guide Column Bushing (Small)](https://www.imspares.com/parts/mc-gz-5/): Small guide column bronze bushing for injection molding machine clamping unit.
- [MC-GZ-6 Guide Column Bushing (Medium)](https://www.imspares.com/parts/mc-gz-6/): Medium guide column bronze bushing for injection molding machine clamping unit.
- [MC-GZ-07 Guide Shaft / Connecting Link](https://www.imspares.com/parts/mc-gz-07/): Guide shaft or connecting link for injection molding machine clamping system.
- [MC-GZ-10 Guide Column Bushing (Large)](https://www.imspares.com/parts/mc-gz-10/): Large guide column bronze bushing for injection molding machine clamping unit.

### Parts of the guide columns

1. **Guide column**: Hardened, ground steel shaft fixed between the plates. The moving plate slides along it and stays square as it travels. Part numbers: MC-GZ-07.
2. **Guide column nuts**: Lock the guide columns into the fixed plates. Plain, castellated and flanged types suit different plate designs. Part numbers: MC-GZ-02, MC-GZ-03.
3. **Guide column bushings**: Bronze or self-lubricating sleeves in the moving plate. They let it slide on the columns and take the wear instead of the columns. Small, medium and large sizes suit different machines. Part numbers: MC-GZ-5, MC-GZ-6, MC-GZ-10.
4. **Injection cylinder**: Hydraulic cylinder mounted on the fixed plate. Its piston moves the moving plate, and with it the screw, to inject the melt into the mold. Part numbers: MC-BC-06.
5. **Injection piston rod**: Hardened, chrome-plated rod that joins the injection piston to the moving plate and carries the injection force. Part numbers: MC-GZ-01.
6. **Lock nut**: Locking jam nut that holds the piston rod in the moving plate and stops it working loose under the repeated injection loads. Part numbers: MC-GZ-04.

## Platens

Fixed and moving platens, platen inserts

- [MC-PP-01 Machine Platen (Movable / Stationary)](https://www.imspares.com/parts/mc-pp-01/): Stationary or movable platen for injection molding machine clamping unit.

### Parts of a platen

1. **Platen**: Cast iron plate the mold half is bolted to. A toggle machine has three: the stationary platen at the injection side, the moving platen and the rear platen behind the toggle. Part numbers: MC-PP-01.
2. **Tie bar bores and bushings**: The four tie bars pass through the corner bores. In the moving platen each bore has a bushing, so the platen slides along the bars without wear. Part numbers: MC-TC-07.
3. **T-slots**: Slots across the platen face for the bolts of the mold clamps that hold the mold half in place. Part numbers: MC-JM-04.
4. **Tapped holes**: Threaded holes in a set pattern, for bolting the mold or its clamps straight to the platen.
5. **Center bore and locating ring**: On the stationary platen the locating ring in this bore centers the mold on the nozzle. On the moving platen the bore lets the ejector rod through. Part numbers: MC-JM-04.
6. **Ejector holes**: On the moving platen, extra holes for ejector rods that push the mold’s ejector plate at several points. Part numbers: MC-ES-08.
7. **Toggle lugs**: Lugs on the back of the moving and rear platens where the toggle links are pinned.

## Toggle & Links

Toggle links, pins, and clamping mechanism components

- [MC-TL-01 Machine Leveling Foot Bolt](https://www.imspares.com/parts/mc-tl-01/): Adjustable leveling foot bolt for injection molding machine installation.
- [MC-TL-02 Toggle Arm / Link Rod](https://www.imspares.com/parts/mc-tl-02/): Toggle arm and link rod for injection molding machine five-point toggle clamping unit.
- [MC-TL-03 Toggle Pin / Hinge Pin](https://www.imspares.com/parts/mc-tl-03/): Toggle hinge pin for injection molding machine toggle clamping mechanism.
- [MC-TL-05 Toggle Link Bushing](https://www.imspares.com/parts/mc-tl-05/): Toggle link bronze bushing for injection molding machine toggle clamping mechanism.
- [MC-TL-07 Anti-Vibration Foot Pad](https://www.imspares.com/parts/mc-tl-07/): Anti-vibration rubber foot pad for injection molding machine floor mounts.

### Parts of the toggle clamping unit

1. **Clamping cylinder**: Hydraulic cylinder on the rear platen. Its rod pushes the crosshead forward to close the mold and pulls it back to open it. Part numbers: MC-CC-01.
2. **Crosshead**: Block on the end of the cylinder rod. It drives the small links that fold and straighten the toggle. Part numbers: MC-CR-02.
3. **Toggle links**: Steel links that fold to open the mold and straighten to close it. Near the straight position they multiply the cylinder’s force into the full clamping force. Part numbers: MC-TL-02.
4. **Toggle bushings**: Bronze bushings in the link bores, where the links turn on the pins. Worn bushings cause play, noise and uneven clamping. Part numbers: MC-TL-05, MC-JM-02.
5. **Connecting rod bushings**: Bushings in the small links that join the crosshead to the toggle links. Part numbers: MC-JM-05.
6. **Toggle pins**: Hardened pins that join the links at each pivot. They carry the full clamping load, so they need regular lubrication. Part numbers: MC-TL-03.
7. **Mold clamps and locating ring**: Clamping plates bolt the mold halves to the platens. The locating ring centers the mold on the stationary platen, in line with the nozzle. Part numbers: MC-JM-04.
8. **Leveling foot bolt**: Adjustable bolt under the machine base, used to level the machine when it is installed. Part numbers: MC-TL-01.
9. **Anti-vibration pad**: Rubber pad under each foot that reduces the vibration and noise passed to the floor. Part numbers: MC-TL-07.

## Clamping Components

Clamping cylinders, wedges, and locking mechanisms

- [MC-CC-01 Clamping Cylinder](https://www.imspares.com/parts/mc-cc-01/): Main clamping (mold locking) hydraulic cylinder for injection molding machine clamping unit.
- [MC-CC-02 Clamping Cylinder — Small / Auxiliary](https://www.imspares.com/parts/mc-cc-02/): Auxiliary clamping or ejection cylinder for injection molding machine.

### Parts of a clamping cylinder

1. **Cylinder barrel and end caps**: Steel tube closed by the rear cap and the front gland. Oil fed through the ports on either side of the piston moves it forward or back. Part numbers: MC-CC-01.
2. **Piston**: Divides the cylinder into two oil chambers. Pressure on one side moves it, and the rod with it, forward or back.
3. **Piston seals (Y-rings)**: Seal the piston against the barrel so oil cannot pass from one chamber to the other. Leaking seals make clamping slow and weak. Part numbers: MC-SB-08.
4. **Piston rod nut**: Holds the piston on the end of the rod. Part numbers: MC-SB-10.
5. **Piston rod**: Chrome-plated rod that carries the cylinder’s force out through the gland to the toggle crosshead.
6. **Rod seals and wiper**: Seal set in the front gland: the rod seals keep the oil in and the wiper keeps dirt out. Part numbers: MC-SB-07.
7. **Auxiliary cylinder**: Smaller cylinder used as a clamping booster or to drive the ejector on some machines. Part numbers: MC-CC-02.

## Tools & Accessories

Screw wrenches, assembly tools, and maintenance accessories

- [MC-GMP-01 Screw Head Wrench (3-Prong / 4-Prong / 6-Prong)](https://www.imspares.com/parts/mc-gmp-01/): Specialist screw head wrench for removing injection molding machine screw heads.
- [MC-GMP-02 Barrel Heating Band Removal Tool](https://www.imspares.com/parts/mc-gmp-02/): Specialized tool for removing and installing heater bands on injection molding machine barrels.

### Service tools for the barrel and screw

1. **Screw head wrench**: Fits over the screw tip so it can be unscrewed from the screw or tightened without damage. Made with 3, 4 or 6 prongs to match the tip. Part numbers: MC-GMP-01.
2. **Screw tip and check ring**: The non-return valve at the front of the screw. It is taken off for cleaning and when the check ring wears.
3. **Screw**: The injection screw, pulled forward out of the barrel to reach the tip. Part numbers: MC-BC-02.
4. **Heater band**: A band clamped around the barrel by a bolt through its two lugs. Ceramic bands crack if they are forced or bent off the barrel.
5. **Heater band removal tool**: Used to take heater bands off the barrel and fit them again without damaging the ceramic, the leads or the thermocouple connections. Part numbers: MC-GMP-02.

## End Caps & Plates

End caps, connecting plates, and mounting hardware

- [MC-ES-08 Ejector Rod](https://www.imspares.com/parts/mc-es-08/): Machine ejector rod for injection molding machine ejector system.
- [MC-ES-09 Ejector Connecting Plate & Pin Kit](https://www.imspares.com/parts/mc-es-09/): Ejector assembly connecting plate and pin kit for Haitian injection molding machines.

### Parts of the ejector

1. **Ejector cylinder**: Small hydraulic cylinder mounted behind the moving platen. It pushes the ejector plate forward to free the part, then pulls it back. Part numbers: MC-CC-02.
2. **Connecting plate and pins**: Plate that joins the cylinder rod to the ejector rods so they all move together. Guide pins through it keep it square. Part numbers: MC-ES-09.
3. **Return springs**: Springs on the guide pins that push the plate back after ejection, so the ejector rods are clear before the mold closes. Part numbers: MC-SR-05.
4. **Moving platen**: The ejector rods pass through holes in the moving platen to reach the mold. Part numbers: MC-PP-01.
5. **Ejector rods**: Hardened rods that carry the ejector force through the platen to the mold’s ejector plate. Part numbers: MC-ES-08.
6. **Mold ejector plate and pins**: Part of the mold, not the machine: the plate carries the pins that push the molded part off the core.

## Seals & Rings

O-rings, piston seals, Y-seals, and hydraulic seal kits

- [MC-SR-05 Return Spring / Ejector Spring](https://www.imspares.com/parts/mc-sr-05/): Return spring and ejector spring for injection molding machine ejector and toggle systems.

## Joints & Mounts

Ball joints, pivot mounts, and mechanical linkages

- [MC-JM-02 Toggle Pin Bushing](https://www.imspares.com/parts/mc-jm-02/): Toggle pin bronze bushing for injection molding machine clamping toggle system.
- [MC-JM-04 Mold Clamping Plate / Locating Ring](https://www.imspares.com/parts/mc-jm-04/): Mold clamping plate and locating ring for injection molding machine platens.
- [MC-JM-05 Toggle Link Connecting Rod Bushing](https://www.imspares.com/parts/mc-jm-05/): Toggle link connecting rod bushing for injection molding machine clamping mechanism.

## Safety Guards

Machine guards, protective covers, and safety enclosures

- [MC-SG-08 Linear Guide Rail & Slider](https://www.imspares.com/parts/mc-sg-08/): Linear guide rail and slider block for injection molding machine injection unit or carriage.

### Parts of a linear guide

1. **Guide rail**: Hardened steel rail bolted to the machine base. Its ground ball grooves guide the carriage in a straight line. Part numbers: MC-SG-08.
2. **Carriage block**: Slides along the rail on rows of steel balls and carries the injection unit carriage with very little friction. Part numbers: MC-SG-08.
3. **Balls**: Steel balls roll between the block and the rail, then return through a channel in the block to roll again.
4. **End caps and seals**: Plastic end caps turn the balls round at each end of the block; rubber seals wipe dirt off the rail.
5. **Grease nipple**: Lubrication point on the end cap. Regular greasing keeps the balls and grooves from wearing.
6. **Mounting bolts**: Bolts fix the rail to the machine base and the block to the carriage. Loose bolts let the unit shift out of line.

## Clamping Mechanism

- [MC-CR-02 Toggle Link / Crosshead](https://www.imspares.com/parts/mc-cr-02/): Toggle clamping system link and crosshead for injection molding machine clamping unit.