Clamp Insert Configurations for Large-Size Butt Fusion Machines: Aluminum, Steel and Anti-Slip Pads
For large-size butt fusion machines, clamp inserts are used to match different pipe diameters and help keep the pipe securely clamped and properly aligned throughout the fusion process.
Welping large-size butt fusion machines are equipped with four clamping rings. Therefore, when this article refers to a “2-piece” or “4-piece” insert design, it means the number of insert pieces used on one clamping ring. A complete machine requires the same insert size to be installed on all four clamping rings, so the total number of insert pieces is four times the quantity used on one ring.
The current configurations are:
| Machine Size | Configuration per Clamping Ring | Total Insert Pieces per Machine |
| 160–800 | 2-piece aluminum inserts | 8 aluminum pieces |
| 1000–1200 | Optional 4-piece aluminum inserts or 2-piece steel inserts | 16 aluminum pieces or 8 steel pieces |
| 1400 and above | 4-piece steel inserts | 16 steel pieces |
In addition, 800 / 1000 / 1200 models can be equipped with optional anti-slip pads to improve pipe holding stability and provide a small adjustment range for slight pipe diameter variations.
160–800: 2-Piece Aluminum Inserts
For 160–800 models, each clamping ring uses a 2-piece aluminum insert.
Since the machine has four clamping rings, one complete insert size requires:
2 pieces × 4 clamping rings = 8 aluminum insert pieces
The aluminum construction reduces the weight of each individual piece, making the inserts easier to handle, install and replace on site.
Main Features
· High-strength aluminum construction
· 2 pieces per clamping ring
· 8 pieces per complete machine set
· Relatively light individual pieces
· Simple installation structure
· Easy to handle and replace on site
· Suitable for 160–800 models
For applications where different insert sizes need to be changed frequently, the 2-piece structure provides a straightforward setup.
1000–1200: Two Clamp Insert Options
For 1000 and 1200 models, two insert configurations are available depending on project requirements and operating preferences:
· 4-piece aluminum inserts
· 2-piece steel inserts
Here again, “4-piece” and “2-piece” refer to the configuration on one clamping ring.
This means that one complete machine set requires:
· Aluminum option: 4 pieces × 4 clamping rings = 16 pieces
· Steel option: 2 pieces × 4 clamping rings = 8 pieces
4-Piece Aluminum Inserts
For 1000 and 1200 models, the aluminum option uses four separate insert sections on each clamping ring.
A complete machine therefore requires 16 aluminum insert pieces for one pipe size.
Compared with a 2-piece structure, each section is smaller and lighter, making manual handling, installation and removal easier.
On 1000 and 1200 machines, the inserts themselves are already relatively large. Dividing each insert into four sections helps reduce the weight that needs to be handled at one time.
The aluminum inserts also feature a widened pipe-contact surface, which helps provide stable clamping and maintain pipe alignment.
Main Features
· High-strength aluminum construction
· 4 pieces per clamping ring
· 16 pieces per complete machine set
· Smaller and lighter individual sections
· Easier piece-by-piece handling and installation
· Widened pipe-contact surface
· Suitable for 1000 and 1200 models
2-Piece Steel Inserts
For 1000 and 1200 models, a 2-piece steel insert configuration is also available.
Each clamping ring uses an upper and a lower steel insert section, so one complete machine set requires 8 steel insert pieces.
The steel inserts are made from precision-cut steel and welded into a rigid structure. Anti-slip serrations on the inner surface help increase friction between the insert and the pipe, reducing relative movement during pipe handling and fusion operations.
Main Features
· Steel construction with high structural rigidity
· 2 pieces per clamping ring
· 8 pieces per complete machine set
· Fewer pieces to install
· Anti-slip serrations on the inner surface
· Stable pipe holding
· Suitable for 1000 and 1200 models
Where a 2-piece structure is preferred or fewer insert sections are more convenient for the operating routine, the steel configuration can be selected.
Key Differences for 1000–1200 Models
| Item | 2-Piece Steel Inserts | 4-Piece Aluminum Inserts |
| Material | Steel | Aluminum |
| Pieces per complete size | 2 | 4 |
| Total pieces per machine | 8 | 16 |
Weight per piece | Relatively heavier | Relatively lighter |
Number of pieces to install | Fewer | More |
Handling | 2-piece installation | Easier piece-by-piece handling |
Pipe-contact design | Anti-slip serrations | Widened contact surface |
Applicable models | 1000 / 1200 | 1000 / 1200 |
The main differences are the weight of each section, the number of pieces to install, and the way the inserts are handled on site.
1400 and Above: 4-Piece Steel Inserts
For 1400 and larger butt fusion machines, each clamping ring uses a 4-piece steel insert.
Since the machine has four clamping rings, one complete insert size requires:
4 pieces × 4 clamping rings = 16 steel insert pieces
As machine size increases, the inserts become significantly larger and heavier. Dividing the insert into four sections makes handling, installation and removal more practical on site.
At the same time, the steel structure provides the rigidity and stability required for very large clamp inserts.
Main Features
· Steel construction
· 4 pieces per clamping ring
· 16 pieces per complete machine set
· Split design for easier handling and installation
· Suitable for 1400 and larger machines
· Selected non-standard sizes can be customized for specific projects
Optional Anti-Slip Pads for 800 / 1000 / 1200 Models
For 800, 1000 and 1200 models, optional anti-slip pads can be installed at the contact area between the machine clamps and the pipe.
They mainly provide two functions:
· Improve pipe holding stability
· Provide limited adjustment for slight pipe diameter variation
1. Larger Contact Area, Less Pipe Slippage
Installing anti-slip pads increases the contact area between the upper and lower machine clamps and the pipe. This also increases friction at the clamping surface.
When the machine moves the pipe forward or backward, the larger contact area helps reduce relative movement between the pipe and the clamps. This helps keep the pipe more stable during facing, heating and fusion.
This can be particularly useful in low-temperature working conditions.
At lower temperatures, PE pipe becomes stiffer and may not conform to the clamping surface as easily. The increased contact area and friction provided by the anti-slip pads can help improve holding stability when moving large-diameter pipe.
This option can be useful for:
· Cold-region projects
· Winter construction
· Large-diameter or heavy pipe
· Applications with relatively high pipe movement resistance
2. Small Adjustment for Slight Diameter Variation
The position of the anti-slip pads can be adjusted within a limited range.
If the actual pipe OD differs slightly from the nominal size, the pad position can be fine-tuned to improve contact with the pipe and provide more stable clamping.
This adjustment is intended for small dimensional variations, such as:
· Slightly non-standard pipe sizes
· Special project pipe
· Pipes with minor OD deviation
If the difference from the standard pipe size is significant, the correct insert size or a customized insert should still be used.
Confirming the Right Clamp Configuration
Before confirming the machine configuration, it is helpful to provide:
· Machine model
· Pipe outside diameter
· Standard or non-standard pipe size
· Whether insert sizes will be changed frequently
· Whether inserts will mainly be handled manually
· Expected working temperature or site conditions
· Whether anti-slip pads are required for 800 / 1000 / 1200 models
With this information, the appropriate clamp insert and pipe-holding configuration can be confirmed before delivery.