1. VMI Group
RETREADING
May-2019

2. VMI Group VMI is well known for new tire production machinery
High quality radial car light truck and truck tires
High output machines
Highly automated; hands-off/eyes-off
Track & trace

4. VMI Group We make machines
2004: VMI integrated the extrusion division of AZ

5. Cushion Gum Extrusion Wingformers for Shoulder shaping

6. VMI’s Cushion to Casing Extrusion Smearing Technology; the principle

7. VMI Group We make machines
How to use this combined know-how in tire retreading

8. Retreading Retread Customers
Fleet owners:
Reliability of deliveries
Total operating costs
Example 18 Ton curtain sider, Km per year
Depreciation, Insurance, Taxes
1/3
Driver
Running cost
Running Costs
Fuel, oil, add blue
72%
Tires 6%
Maintenance, repairs
22%
Fuel efficiency and reliability is more important than the mere price of a tire
The tread has a large affect on the overall rolling resistance of the tire

9. Retreading Business Challenge
Price pressure / low priced new tires
Quantity and quality of casings
Find good personnel and provide training

10. Retreading Automation challenge
A retread is different from a new tire
Tires are mixed (size, brand, type)
Casings vary, each has a different history, 1st retread…. 2nd
Many treads to choose from
Matching thread profiles over splice or not
Tire with different purposes: highway, city, mining, off road..
So it is a High-Mix, Low-Volume production
Need: flexible & robust machines, low cost, easy to operate and to maintain

11. VMI Retreading Machinery
VMI focus on ‘cold’ (pre-cured tread) retreading
Cushion gum application by extrusion smearing
Optional with integrated Builder
Other suppliers offer:
Various testing equipment (example Shearographic)
Computer controlled buffing
Ring-tread or Uni-circle builders

12. Tread applicator
On the same machine immediately after applying cushion gum
Cushion Gum still hot, sticky and clean
Design for:
Pre-cured tread (cold process)
Splice with pattern matching (requires stretching)
Main points:
Tread in the center of the tire
Tread in a straight line on the tire (no snaking)
Good splice matching
Balanced tread stretching

13. Tread applicator Adjustments
Controls in the applicator:
Prepare the tread on the table
Align the tread center to casing
Stretch the tread to match the casing circumference

14. Tread applicator Application
Follow the tire circumference speed to complete the application.

15. Stitcher Unit

16. Automation So there are modules for: Cushion gum extrusion
Tread application
Stitching
We still need information required for control:
Tire diameter, width and center
Tread length, width and thickness
To adjust for example:
Wingformer positions
Center to center alignment
Stretching and application speed

17. Tread Applicator Tire scanning camera
The camera is actually a: Laser light and camera in a single box
Camera
Laser
Beam
Reflected
Light
Casing

18. Camera Scan Laser Line Laser scan to measure: Casing Width Center
Diameter
A special software algorithm is designed to calculate the position of the shoulders and then to calculate the center line

19. Camera Scan Camera Picture
Before cushion gum extrusion.
The scan signal from the camera. Note the skive holes on several scan lines.
With cushion gum, before Tread application.

20. RETRAX Builder Automatic Cushion gum extruder and Tread Applicator
Automatic Centering of the tread to the casing
Automatic length checking and stretching
Error message if tread length out of range
Fast
Automatic stitcher
High product quality

21. Thank You
For your
Attention