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Tire retreading
- Cushion gum extruder (CTC)
- Earthmover tire retread systems
- OTR Strip builder for treads
- Baldwin BSEL150 endless belt strip extrusion line for OTR tire repairs
Cushion gum extruder (CTC)
The VMI-AZ Extrusion CTC (Cushion-to-Casing) system directly extrudes hot cushion gum onto a buffed casing therefore replacing the process of wrapping calendared sheet cushion gum around the casing. A single extruder feed strip is drawn into the feeder section, heated through plastisisation in the mixing section of the extruder then forced through the 420mm wide CTC extrusion head and onto the buffed casing.
With the CTC skive filling action being fully automatic, the process is significantly more reliable than performed by an operator with a hand held extruder. Cushion gum width is selected through moveable slides that alter the die opening width of the extrusion head and specially shaped swift-change side dies are available to ensure the cushion gum can be partially extruded on the casing shoulder to accommodate pre-cured tread with single or contour sides.
The pictures show Skive filling and Cushion gum smearing process-like butter smearing on bread.
The VMI-AZ Extrusion CTC system is available in both the CTC-SB I and CTC-SB VII model options. The main features of the CTC-SB I include optimization for large production units with the capacity to handle up to 80 16 inch tires during an eight hour production shift (including cushion gumming and pre-cure tread building.
Other benefits include:
- PLC controlled with touch screen HMI
- Automatic tread stretching for precise splice matching
- Reduced labor costs through automatic skive filling
- Single size feed strip for reduced cushion gum costs
- Correctly formulated cushion gum for reduced cement spraying costs
- Increased product quality
The picture shows the CTC-SB I extruder builder.
The main features of the CTC-SB VII include optimization for both small and large production units and the capacity to produce up to 140 tires each individual shift.
Other benefits include:
- PLC controlled with touch screen HMI
- Reduced labor costs through automatic skive filling
- Single size feed strip for reduced cushion gum costs
- Correctly formulated cushion gum for reduced cement spraying costs
- Increased product quality
- Discounted models available without stitching unit and laser arm (for cushion gum application only)
The picture shows an CTC-SB VII extruder builder .
Earthmover tire retread systems
Apart from being one of the market leaders for retread systems in passenger and truck tires, VMI-AZ also offers a specialized system for the professional retreading of earthmover tires which incorporates main components of a base constructor and strip builder.
The base constructor consists of three PIN-type extruders that are attached to a special extrusion head which supplies rubber to the tire carcass. The rubber is smeared onto the carcass whilst it is rotating and once the base has been built up (by the base constructor), the tire is moved to the strip builder position where a hot extruded rubber strip is applied to the carcass to form the new tread.
The picture shows the VMI-AZ base constructor for earth mover tires retreading.
For assured high precision throughout the process the Shark® extruder gear pump system is implemented when extruding the strip. This innovative cushion to casing technology is now receiving ongoing approval within the industry.
OTR Strip Builder for Treads
The VMI-AZ Extrusion OTR Strip Builder builds-up the tread of OTR tires. This building system consists of a gear pump extruder system, a tire stand and the control system.
Thanks to the volumetric gear pump the strip is extruded onto the carcass directly. The strip apply position and the tread build-up is controlled by the laser sensor and the software program. Customers’ different tread requirements can be stored in the HMI.
The picture shows the principle of the OTR Strip Builder
VMI-AZ Strip Builder offers the following advantages:
- Direct strip apply – no calender required
- Gear pump delivers high output precision
- Close distance between die and tire surface
- Gear pump allows usage of short screw – low temperature reduces risk of scorching
- Different strip sizes possible by just changing the die
The picture shows the strip building in progress
Baldwin BSEL150 endless belt strip extrusion line for OTR tire repairs
Steel cord strip is one of the essential components used in retreading and repairing large OTR tires and the Baldwin belt strip extrusion line produces an continuous belt strip from rubber compound and steel cords and automatically winds the produced strip onto reels for further use in OTR repairs. The strip is cut to length to replace broken steel cables in the tire.
The complete line consists of a dual position creel and organiser unit, cold feed pin type extruder with gear pump, pull unit, festooner, optional infrared cord heating unit, a wind-up system tailored to individual needs and a highly advanced control system.
The picture shows steel cords which are pulled from the creel.
Rubber compound that's added to the steel cords by a VMI-AZ Extrusion gear pump extruder. Accurate quality and dimension control of the produced strip is achieved by the VMI 3D Vision system.
The picture shows the produced strip is automatically wound onto reels.
For more information please see our brochures or contact us sales [at] vmi-group [dot] com.
