When to change VSI Wear Parts?

VSI Wear Parts

VSI crusher wear parts are usually located inside or on the surface of the rotor assembly. Choosing the right wear parts is critical to achieving the desired performance. For this, parts must be selected based on the feed material’s abrasiveness and crushability, feed size, and rotor speed.

The wear parts for a traditional VSI crusher included:

• Rotor tips
• Back-up tips
• Tip/cavity wear plates
• Upper and lower wear plates
• Distributor plate
• Trail plates
• Top and bottom wear plates
• Feed tube and feed eye ring

When to change?

Wear parts should be replaced when they are worn or damaged to the point that they no longer work effectively. The frequency of replacement of wear parts depends on factors such as the type and quality of feeding material, the operating conditions of the VSI, and the maintenance practices followed.

It is important to regularly inspect wear parts and monitor their condition to ensure they are operating at peak efficiency. You can decide whether the wear parts need to be replaced by some signs, such as reduced processing capacity, increased energy consumption, excessive vibration, and abnormal wear of parts.

There are some recommendations from crusher manufacturers for reference:

Back-up tips

The back-up tip should be replaced when there is only 3 – 5mm of depth left of the Tungsten insert. They are designed to protect the rotor against a failure in the Rotor Tips and not for prolonged use!! Once these are worn through, the mild steel Rotor body will wear away very fast!

These must also be replaced in sets of three to keep the rotor in balance. An out-of-balance rotor will damage the Shaft Line assembly over time.

Rotor tips

The rotor tip should be replaced once 95% of the Tungsten insert has been worn away (at any point along its length) or it has been broken by large feed or tramp steel. This is the same across all tips for all rotors.The Rotor tips must be replaced using the packaged sets of 3 (one for each port, not all on one port) to make sure that the Rotor is kept in balance. If a tip is broken try and replace that one with a stored tip of similar wear to the others on the rotor.

Cavity Wear Plates + Tip CWP.

The Tip Cavity & Cavity Wear Plates should be replaced as wear starts to appear on the bolt head (holding them on). If they are reversible plates they can also be reversed at this time to give double the life. If the bolt head in the TCWP position is worn away it can become difficult to remove the plate, so regular inspection is essential. The T/CWP must be replaced in sets of 3 (1 for each port) to make sure that the Rotor is kept in balance. If a plate is broken try and replace it with a stored plate with similar wear to the others on the rotor.

Distributor Plate

The Distributor plate should be replaced when there is only 3-5 mm left at the most worn point (normally around the edge), or the Distributor bolt has started to wear. The Distributor bolt has a high profile and will take some wear, but care must be taken to protect it. A cloth or silicone should be used to fill the bolt hole for protection. Two-piece Distributor plates can be turned to give added life. This can be done through a port without removing the Roof of the machine.

Upper + Lower wear plates

Replace the Upper and Lower wear plates when there is 3–5 mm of plate remaining at the center of the wear path. The lower wear plates generally wear more than the upper wear plates due to underutilization of the rotor’s maximum throughput and the use of an incorrectly shaped trail plate. These plates must be replaced in sets of three to make sure that the Rotor is kept in balance.

Feed Eye Ring and Feed Tube

The Feed eye ring should be replaced or rotated when there is 3 – 5mm left of the Upper wear plate at its most worn point. The Feed tube must be replaced when its bottom lip wears past the top of the Feed eye ring. The new Feed tube should extend past the top of the FER by at least 25mm.If the Rotor build-up is too high these parts will be worn much faster and will let material spill out onto the top of the Rotor. It is important that this does not happen. The Feed eye ring can be rotated up to 3 times when worn.

Trail Plates

The Trail plates need to be replaced when either the Hard facing or Tungsten insert on the leading edge has been worn away. If they are not replaced at this point it will affect the Rotor build-up, which can reduce the life of the other Rotor wear parts. Although these parts are the most inexpensive, they are often called one of the most important.