We Recommend Periodic Inspection and Timely Replacement of Induction-Heated Jacket Rolls

Induction-Heated Jacket Rolls may become more susceptible to failures or accidents over time due to normal wear and aging.
If a failure occurs, repairs typically require at least several days. In some cases, depending on the condition of the roll, repair may not be possible, and manufacturing a replacement roll may take several months.

To prevent unexpected failures and production downtime, we recommend performing regular inspections and planning for timely replacement of the rolls.

Maintenance and Inspection Items

For rolls that have been in service for a long period without any maintenance, we recommend starting with a maintenance inspection.

1. Replacement of Internal Bearings

The induction coil is supported by bearings installed inside the shaft.
If the grease in these bearings becomes insufficient, the induction coil may begin to rotate with the roll shell. This can lead to bearing damage and damage to the induction coil.

To prevent such failures, we recommend scheduled replacement of the internal bearings before problems occur.

Depending on the installation conditions of the roll, bearing replacement can often be performed on the machine.

2. Inspection of Roll Surface Temperature Distribution

After long-term operation, the temperature distribution across the roll surface may deteriorate over time. This can lead to product quality issues, so periodic inspection of the roll surface temperature distribution is recommended.

If deterioration in temperature uniformity is detected, the roll can be repaired by sending it to our Makino Factory.

3. Inspection of the Induction Coil

Deterioration of the insulation may lead to ground faults or short-circuit failures.
Since it is difficult to determine the remaining service life of the induction coil based on visual inspection alone, we recommend replacement according to the recommended service interval.

The recommended replacement interval varies depending on the specifications of the roll.

Replacement / Upgrade

Induction-Heated Jacket Rolls manufactured before 1995 have the following structural and specification characteristics. For this reason, early replacement or upgrading is recommended.
(Some rolls may not fall under these conditions. Please contact us for details regarding your specific roll.)

1. Jacket Chamber with Double-Tube Structure

In rolls with a double-tube jacket chamber structure, long-term use may lead to aging and mechanical stress, which can cause buckling of the inner tube or cracking at welded joints.
In such cases, repair is difficult and replacement of the roll is typically required.

The current standard design uses a drilled roll structure, in which multiple drilled channels are formed within the thickness of the roll shell. This structure provides greater mechanical strength and durability.

2. Induction Coil with Wound Iron Core

When the iron core of the induction coil deteriorates, the temperature of the core tends to increase, which may lead to coil burnout.

The current standard uses a laminated involute iron core, which has lower iron loss compared with the wound iron core.
As a result, the iron core temperature remains lower, contributing to longer service life.

3. Induction Coils Using Asbestos as Insulation Material

Some induction coils use asbestos-containing insulation material.
Since the material is non-friable, continued use does not present an immediate problem. However, coils using this material cannot be rewound or repaired.

If the induction coil fails, it will be necessary to replace it with a new induction coil using non-asbestos insulation materials.

4. Temperature Detector Utilizing Slip Ring Method

Contact-type slip rings are no longer adopted due to concerns with detection accuracy and maintainability, as well as the increased cost of replacement parts.
We recommend upgrading to the current standard; a non-contact temperature detector using the rotary transformer method.

When an Induction-Heated Jacket Roll Is No Longer Required

Induction-Heated Jacket Rolls contain various working media sealed inside the jacket chamber.
Before recycling or disposal, the sealing plug of the jacket chamber must be opened. If this is not done, the internal pressure of the jacket chamber may increase during processing, which could cause the roll shell to rupture.

In addition, some of the working media used may be flammable / hazardous substances or regulated chemical substances that require special handling and recovery. Therefore, these media must be properly recovered prior to recycling.

Some induction coils may also contain asbestos. In such cases, the asbestos must be removed by a licensed and qualified contractor before recycling or disposal.

Since the required handling procedures depend on the specifications of the roll, please contact us so that we can confirm the specifications of the applicable roll.

If you complete the required information on the transfer certificate and send the Jacket Roll to our Makino Factory, we can also carry out the appropriate recycling and disposal procedures on your behalf.