TPE粘金属材料怎么选?模温没到,料先发脾气

应用领域 发布时间: 2026-09-13 4635 阅读

The insert doesn’t stick well during injection molding and falls off as soon as it’s pried. The mold temperature isn’t right, so the material gets upset with the insert first.

It comes off as soon as you pry it; it's not poor material, it's that the mold temperature hasn't reached the required level.

TPE bonding with metal inserts is determined by mold temperature: preheating of inserts, correct mold temperature, and coordinating material temperature. Here's the conclusion first: if the metal is cold, the material will refuse to stick as soon as it is injected — mold temperature is the first hurdle for adhesion.

The biggest pitfall of TPE bonding with metal: the material gets fussy before the mold temperature is reached. If the mold temperature is too low, the material won't stick—the mold temperature is the switch for insert bonding.

TPE inserts are a matter of craftsmanship: falling off or cracking are all problems. Only when the process is correct will the bonding be stable—it's craftsmanship, don't skip steps.

Temperature determines stickiness, so why preheat the inserts first

Metal inserts absorb heat quickly: without preheating, the material is cold first. Preheat the insert to 80-120°C, only then will the material stick — preheating is the starting point of bonding.

The mold temperature should be higher: SEBS-based 40-60℃. If the mold temperature is low, the adhesion is poor—mold temperature is the line of adhesion.

Material temperature also needs to be coordinated: 180-210°C. If the material temperature is low, the filling will be insufficient — material temperature is the line for filling.

Preheating, injection molding, cooling—what is the process flow?

Preheating: Preheat the insert properly. If the insert is not hot, it won't stick—preheating is the starting point of bonding.

Injection molding: overmold injection molding, temperature adjusted according to the system. The two-stage temperature control— injection molding is the core of bonding.

Cooling: Maintain pressure and cool in place. Insufficient cooling leads to detachment—cooling is the finishing touch of bonding.

Different metal inserts, where are the differences in surface treatment?

InsertPreheatMold temperature
Aluminum part100℃50℃
Copper part110℃55℃
Steel part120℃60℃
Stainless steel130℃65℃

Table reading: Preheat the inserts according to the material, and follow the mold temperature—different metals, different temperatures.

Adjust according to the insert, then the bonding will be firm.

Sticks firmly without falling off, first check these four items

ProjectRequirementJudgment
PreheatBy add-inMeet the standard
Mold temperatureAccording to the systemMeet the standard
Material temperatureAccording to the systemMeet the standard
Peel strengthActual measurementMeet the standard

Table reading: List the preheating temperature of the insert, mold temperature, and material temperature in a table — if the metal is not preheated, the soft rubber won't stick firmly.

Mold temperature is the first step in bonding.

If the insert is not preheated, the bonding strength is zero.

Pitfall 1: Not preheating. Install the inserts at room temperature, and the seams will separate first—before bonding to metal, preheat the insert to the set temperature.

Pitfall 2: Messy mold temperature adjustment. Falling off — adjust the mold temperature according to the insert.

Pitfall three: insufficient cooling. Falling off — cooling in place.

Mold temperature, preheating, surface—ask before bonding

Three questions: what kind of insert, what system, and what is the peel strength. One verification: actual measured peel strength from trial mold—three questions and one verification, the supplier's details are clear.

Mold temperature verification must be done first: preheat the insert and reach the mold temperature before injection molding, and measure the peel strength by batch. Check the mold temperature first, then discuss bonding—mold temperature is the first hurdle for bonding.

Make sample retention a habit: retain samples for each batch and retest bonding by batch. When changing materials for a batch, compare first before scaling up — stable batches lead to fewer customer complaints.

Peeling, Flashing, Missing Glue: A Table for Fault Comparison

PhenomenonReasonCountermeasure
fall offLow mold temperatureDie temperature
fall offDo not preheatAdd preheat
CrackingMaterial mismatchMaterial change
Shortage of materialsMaterial temperature is lowIncrease material temperature
Silver streakMoistAdd roasting material

For insert bonding, look at the peel strength. Metal inserts usually require pretreatment and a special adhesive formulation. Different insert materials require different preheating temperatures; the surface must be properly degreased, as bonding will not be strong on a dirty surface.

The insert comes off as soon as you twist it; don’t blame the glue first—the mold temperature hasn’t reached the required level, so the material is 'acting up'. Temperature is the temper switch for bonding; a slight difference in temperature leads to poor bonding. Holding pressure affects compactness; if it is insufficient, it will fall off.

Three steps for bonding metal acceptance: surface pretreatment, preheating according to material, and measuring peel strength. Test molds should be produced in small batches first, and mass production should only proceed when the peel strength meets the standard; pressure-holding parameters should be recorded in the process card and executed according to the card.

Metal inserts are the 'cold bones,' TPE is the 'soft part'—if the temperature is too low, they can't grip each other tightly. Moisture also causes trouble; the material needs to be properly dried; cooling must be even, otherwise stress will remain.

The peel strength refers to the bonding requirement value, with no separation after 500 hot and cold cycles. Insert parameters are recorded and archived; for similar issues, first check the ledger, and before changing materials, first compare the peel strength.

TPE sticks to metal not by relying on glue, but by hard stacking; the polarity of the substrate and surface treatment are the roots of adhesion.

After degreasing, sandblasting, or priming pretreatment of the metal surface, the special adhesive formula can only achieve high peel strength; directly bonding the steel sheet results in low peel strength, comes off over time, and the insert temperature also needs to be maintained.

The acceptance of metal overmolding is based on peel strength and salt spray, not the feel of new material.

For insert overmolding, first test the peel strength, then bend, and lastly perform salt spray; if the peel strength is too low, do not mass produce. When changing materials, first do small batch tests with crosshatch and peel tests, and track data with each batch.

Metal coating finishing inspection: Peel strength, cross-cut, and salt spray tests are conducted with each batch.

Do not mass-produce if the peel strength of each batch sample is too low. No peeling occurs after salt spray test; when changing materials for a batch, first conduct a small batch cross-hatch adhesion test, and increase production according to batch data.

When it comes to selecting adhesives for metals, it ultimately comes down to asking about surface treatment, peel strength, and salt spray all at once.

Metal degreasing, sandblasting, or priming; the special formula's stripping power is required to apply it. First test the stripping, then conduct the salt spray test; the data follows each batch before scaling up.

Cologne Customer Case: Flame Retardant Failed Inspection, Export Blocked; Sample Data Passed Inspection

A plastic injection processing factory in Chengdu had TPE insert parts that failed the flame retardancy inspection, causing export delays. Cologne assisted by providing samples and physical property data from the same batch, and the flame retardancy grade passed the inspection, allowing smooth export. With samples and data, the export passed in one go — for flame retardancy issues, first look at the additive system.

Summary

The process of TPE bonding to metal: first check the mold temperature, preheat before starting. If the mold temperature hasn't reached the required level, the material will get temperamental. Mold temperature is the first crucial step.

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