Clamp Insert Configurations for Large-Size Butt Fusion Machines: Aluminum, Steel And Anti-Slip Pads

Large-size butt fusion machines use clamp inserts to accommodate different pipe diameters and keep the pipe securely positioned and properly aligned throughout the fusion process.

Welping large-size butt fusion machines are equipped with four clamping rings. In this article, a “2-piece” or “4-piece” insert refers to the number of insert sections installed on each individual clamping ring.

Since the same insert size is fitted to all four clamping rings, the total number of insert pieces required for one complete machine is four times the number used on a single ring.

For 800, 1000 and 1200 models, optional anti-slip pads are also available to improve pipe holding stability and provide limited adjustment for small pipe diameter variations.

160–800: 2-Piece Aluminum Inserts

For 160–800 models, each clamping ring uses a 2-piece aluminum insert.

With four clamping rings on the machine, one complete insert size consists of:

2 pieces × 4 clamping rings = 8 aluminum insert pieces

Aluminum helps keep the individual insert sections relatively light, making them easier to lift, install and replace during field operation.

Main Features:

· High-strength aluminum construction

· 2 pieces per clamping ring

· 8 pieces per complete machine set

· Relatively lightweight individual sections

· Simple installation structure

· Easy to handle and replace on site

· Suitable for 160–800 models

For projects where insert sizes need to be changed regularly, this 2-piece design provides a simple and practical setup.

1000–1200: Two Clamp Insert Options

For 1000 and 1200 models, two clamp insert configurations are available:

· 4-piece aluminum inserts

· 2-piece steel inserts

Both designs provide secure pipe clamping, but they differ in material, piece size, handling and installation method.

A complete machine requires:

· 4-piece aluminum option: 4 pieces × 4 clamping rings = 16 pieces

· 2-piece steel option: 2 pieces × 4 clamping rings = 8 pieces

The choice can be made according to project requirements and operator preference.

4-Piece Aluminum Inserts

On 1000 and 1200 models, the aluminum insert is divided into four sections on each clamping ring.

One complete insert size therefore consists of 16 aluminum pieces.

At these machine sizes, clamp inserts are already relatively large. Dividing each ring insert into four smaller sections reduces the weight of each individual piece, making manual installation and removal more manageable.

The aluminum inserts also feature a widened pipe-contact surface, helping provide stable clamping and support accurate 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

· Widened pipe-contact surface

· Suitable for 1000 and 1200 models

For operators who frequently install or remove large inserts manually, the smaller individual sections can make daily handling considerably easier.

2-Piece Steel Inserts

A 2-piece steel insert configuration is also available for 1000 and 1200 models.

Each clamping ring uses one upper and one lower steel insert section, giving a total of 8 steel pieces for the complete machine.

The inserts are manufactured from precision-cut steel and welded into a rigid structure. Anti-slip serrations on the inner surface increase friction between the insert and the pipe, helping reduce relative movement during pipe positioning, facing and fusion.

Main Features：

· Rigid steel construction

· 2 pieces per clamping ring

· 8 pieces per complete machine set

· Fewer sections to install

· Anti-slip serrations on the inner surface

· Stable pipe holding

· Suitable for 1000 and 1200 models

This option is suitable where operators prefer a simpler 2-piece structure with fewer insert sections to install.

Key Differences for 1000–1200 Models

The main difference is not simply aluminum versus steel. It is also a matter of how the inserts are handled on site.

The 4-piece aluminum design divides the insert into smaller, lighter sections, while the 2-piece steel design uses fewer but heavier sections. The preferred configuration therefore depends largely on installation habits, handling conditions and project requirements.

1400 and Above: 4-Piece Steel Inserts

For 1400 and larger butt fusion machines, each clamping ring uses a 4-piece steel insert.

One complete insert size therefore requires:

4 pieces × 4 clamping rings = 16 steel insert pieces

As machine size increases, clamp inserts become substantially larger and heavier. A four-section design makes installation and removal more practical by reducing the size of each individual piece.

At the same time, steel construction provides the rigidity and structural stability required for very large insert sizes.

Main Features“

· Steel construction

· 4 pieces per clamping ring

· 16 pieces per complete machine set

· Split design for more practical handling

· 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 between the machine clamps and the pipe.

They serve two main purposes:

· Improving pipe holding stability

· Providing limited adjustment for slight pipe diameter variations

1. Increased Contact Area for More Stable Pipe Holding

Anti-slip pads increase the contact area between the machine clamps and the pipe, which in turn increases friction at the clamping surface.

When the machine moves the pipe forward or backward, this additional contact helps reduce relative movement between the pipe and the clamps. The pipe can therefore remain more stable during facing, heating and fusion.

This can be particularly useful when handling large-diameter pipe with relatively high movement resistance.

Low-temperature applications are another situation where additional holding force can be helpful. As PE pipe becomes stiffer in colder conditions, it may conform less easily to the clamping surface. The larger contact area provided by the anti-slip pads helps maintain a more secure grip on the pipe.

Typical applications include:

· Cold-region projects

· Winter construction

· Large-diameter or heavy pipe

· Applications with relatively high pipe movement resistance

2. Limited Adjustment for Slight Pipe Diameter Variations

The anti-slip pads can also be adjusted within a small range.

If the actual outside diameter of the pipe differs slightly from the nominal size, the pad position can be fine-tuned to improve contact between the clamp and the pipe.

This can be useful for:

· Slightly non-standard pipe sizes

· Special-project pipes

· Pipes with minor OD variations

The adjustment range is limited. If the pipe diameter differs significantly from the standard size, the correct insert size or a customized insert should still be used.

How to Confirm the Right Clamp Insert Configuration

Before confirming the machine and insert configuration, it is useful to provide the following information:

· Machine model

· Pipe outside diameter

· Whether the pipe size is standard or non-standard

· How frequently insert sizes will be changed

· Whether inserts will mainly be handled manually

· Expected working temperature and site conditions

· Whether anti-slip pads are required for 800 / 1000 / 1200 models

With these details, the most suitable clamp insert and pipe-holding configuration can be confirmed before delivery.