In laminated glass production lines, EVA film often slips and adheres to the roller. Is the problem temperature control or tension control?

Roller skid and stickiness are common symptoms of roller skid, and many people's first reaction is that the temperature is not controlled properly or that the film is too soft to stick to the roller. Wrong. The real problem is probably nerves; temperature control is just an accessory. Today we reveal the secrets, and when you're done, you'll know which knob to adjust first.
First, let's define the question: are skidding and sticking to the roller two or one?
The slip is caused by uneven lateral tension, which leads to film slip and misalignment. Adhesion to the roller is due to excessive friction between the film surface and the roller, resulting in entanglement. On the surface, they appear to be two different things, but on EVA laminated glass production line, they are often two manifestations of the same root cause-uncontrolled tension.
When the winding tension is too high, the EVA film will be overstretched and the internal stress between the film layers will increase sharply. This internal stress causes the film to constantly try to "shrink" as it runs. When retraction force is not evenly distributed horizontally, the film moves sideways, sliding sideways. At the same time, excessive tension causes the film surface to be pressed tightly on the guide rollers and cooling roller. EVA itself is a highly viscous material that softens at high temperatures, becomes sticky and then gets tangled up in the drum. So, what you see as "dislocation and roller paste" are essentially two strained outcomes.
Stress is the culprit, as three pieces of evidence confirm:
Evidence 1: Rapid acceleration and deceleration are the number one killers of disorders. When acceleration time is less than 120 seconds and deceleration time less than 80 seconds, the smooth films are prone to slip and dislocation, according to industry test data. EVA film has a smooth surface, low friction coefficient and is extremely sensitive to velocity change. If your production line starts and stops frequently, or adjusts too quickly, tension fluctuations can spread like dominoes throughout the film, making dislocation almost inevitable.
Evidence 2: Excessive winding tension leads directly to both edge delamination and dislocation. During production EVA film are wound with too much tension, stretching the film. When glass is made, the film shrinks, resulting in edge delamination and loss of adhesives. This retraction force is not uniformly released; it creates tension difference on the side, allowing the film to naturally drift sideways with less tension. Too much pressure also presses the film to the surface of the roller, causing the roll to stick.
Exhibit 3: A common blind spot is the unresponsiveness of engineering, procurement and control systems. Many production lines have EPC sensors that are not sensitive enough or have faulty actuators. By the time the system detects the deviation and corrects it, the film had drifted significantly. This is especially true of wide EVA films, which have large lateral spans, making it exponentially more difficult to maintain tension uniformity --somethingordinary EPC systems simply cannot keep up with.
Temperature control was complicit, but not the mastermind. Is temperature control responsible? Yes, but only marginally.
The lamination temperature of EVA is about 110°C on the glass surface and 130°C in hot air. If the temperature is too high, the fluidity of the EVA increases, the film layer becomes soft, and it is indeed easier to stick to the drum. However, high temperatures do not directly cause bias --the core of the bias is uneven lateral force; temperature only increases roller adhesion.
Conversely, if the temperature is too low, the EVA will not be sufficiently plasticized, causing the film to harden and become brittle. Although it will no longer stick to the roller, it can develop ridges, wrinkles and not even close enough to bond after laminating, leading to decolletage. Therefore, the correct temperature control method is not ``cooling and anti-sticking '', but ``control the temperature in the process window."
A more insidious temperature control trap is lateral temperature difference. If the temperature difference between the body of the furnace is more than 10 degrees Celsius, the film's hardness will be inconsistent. The softer side will have more friction and resistance, causing the film to drift to the harder side. In this case, there is no point in maximizing tension because the fundamental problem lies temperature uniformity.
There are three steps to solving this problem: tighten and then control the temperature.
Step 1: calibrate the tension curve. The initial tension during winding should not be too high. It is recommended to start with low tension and gradually increase tension in order to find a critical mass to prevent deviation. Special attention should be paid to products with smaller slits, as overstretching can lead directly to lateral slippage. taper tension should decrease gradually with the increase of the roll diameter.
Step 2: Control the speed. Set your acceleration time to 120 seconds and your deceleration time to 80 seconds. Rapid acceleration and deceleration can be fatal to the smooth surface of EVA film, with 80% of deviations occurring during this phase.
Step 3: Check the temperature difference. Use a temperature gun to scan the transverse temperature distribution of the heater, and the difference between the temperature and the temperature should be controlled to within 5°C. Huge temperature differences can render even the best tension adjustment unhelpful.
Simply put: if deviation and drum bonding occur at the same time, check first the tension and then the temperature control. Tension is the cause, roller bonding is the result, and temperature control is the amplifier. Lock the tension curve, slow down, control the temperature difference-do all three things right and you can solve more than 80% of deviation and roller jamming problems. When problems arise, do not immediately lower the temperature, this is only a palliative, too cold can lead to stratification.