防尘罩仨月就脱层进沙，制动件磨出沟。制动防尘罩选料踩空，返工比买料还贵。
结论先摆：制动防尘罩，硬度粘接绑一起看
制动防尘罩是“制动件上的皮”：防尘、防沙、防水。
材料要硬度合适、粘接牢、回弹好。
结论先给：SEBS 基 TPE 是主流。包胶件要粘接牢，上粘接配方或 TPV。
硬 10 度手感差一档，硬度偏一档装配手感全变——Shore A 50-70 按装配工况定，硬度是防尘罩的锚点。
制动防尘罩是“功能件”：防尘失效，制动件进沙。材料选对，功能才有底——功能件，别省料钱。
TPE凭啥胜出：硬度随便调，包胶没人比
制动防尘罩用 TPE 的理由：硬度可调、包胶成熟、回弹好、成本可控——四条合起来，适合防尘罩。
硬度是核心：太硬装配难，太软塌。硬度 Shore A 按装配工况定。
包胶脱层是包胶件的死法，剥离强度按标准写进验收——TPE 包金属或尼龙骨架，剥离不牢用久就分层。
三个工况考它：摩擦、温度、制动液
摩擦工况：制动件摩擦粉尘。耐磨、耐尘数据要验——磨穿防尘罩，制动件进灰。
温度工况：制动件发热。耐温按实际温度验——温度不够，防尘罩就软化。
介质工况：制动液、油污。耐介质数据要验——泡液膨胀，防尘失效。
TPE还是橡胶：一张表说清
| 维度 | TPE（SEBS 基） | 橡胶 |
|---|
| 硬度 | A40-80 可调 | 可调 |
| 包胶粘接 | 成熟 | 需处理 |
| 回弹 | 可调 | 好 |
| 成型 | 注塑 | 硫化 |
| 成本 | 低 | 中高 |
| 批次 | 稳 | 波动大 |
表格读法：橡胶回弹好但工序多、批次波动；TPE 效率高、批次稳、包胶成熟——量产件，TPE 是主流。
高弹场景（频繁伸缩），高回弹 TPE 配方——按功能选。
三个死穴：硬度飘、脱层、泡液胀
坑一：硬度漂移。批次间硬度飘——批次报告，比牌号名字值钱。
坑二：包胶脱层。包胶件用久脱层——剥离强度测试，写进验收。
坑三：耐介质漏测。泡制动液膨胀——耐介质数据，必测。
到货验这三笔账：硬度、剥离、耐介质
三问：硬度按什么标准、剥离强度多少、耐介质按什么条件。一验：按实际装配打样——三问一验，供应商底细清楚。
包胶验证要实测：剥离、弯折。实测最硬——脱层一次，返工一堆。
留样要成习惯：每批留样，硬度粘接按批次复测。批次换料先对比再放量——批次稳，客诉少。
包胶窗口锁死：模温、料温、保压
包胶窗口三参数锁死：模温、料温、保压——三参数对包胶才牢，脱层多是温度窗口没找准。
模温影响粘接：模温太低粘接不牢，按配方建议值调。
料温影响流动：料温太高降解变色，按牌号窗口控。
保压影响密实：保压不足表面缩痕，按件形调。
| 包胶参数 | 窗口 | 影响 |
|---|
| 模温 | 按配方 | 粘接强度 |
| 料温 | 按牌号 | 流动/降解 |
| 保压 | 按件形 | 密实度 |
| 冷却 | 按壁厚 | 尺寸稳定 |
表2读法：包胶四参数，锁死才稳。脱层，多是温度窗口没找准。
| 材料指标 | 要求 | 说明 |
|---|
| 硬度 | A50-70 | 手感装配 |
| 剥离强度 | 按标准 | 包胶牢 |
| 回弹 | ≥50% | 功能件 |
| 耐介质 | 按实际 | 不膨胀 |
表3读法：四指标是防尘罩的体检表。硬 10 度，手感差一档。
装配过盈量不同硬度要求不同，按实际装配读数据——硬度 A50-70、回弹 ≥50%，装配对了硬度才不踩空。
制动防尘罩的供应商，问四句：什么体系、剥离强度多少、硬度按什么标准、变更会不会通知。四句问完，底细清楚——问对问题，比压价有用。
打样时把包胶按连续生产模拟一次：温度累积，窗口会漂。
连续工况过了，单件更稳——模拟连续，比只看单件全面。
装车跑制动试验，高温和摩擦一起考——实车制动过了批量才敢放，连续生产温度累积窗口会漂，连续工况先模拟。
科隆客户案例：包胶批量脱层，调参数对标复现
马鞍山一家汽车零部件厂，制动防尘罩包胶件批量脱层，返工率居高不下。科隆配合调整注塑参数（模温/料温/保压），手感回弹对标样品复现，脱层问题消失。参数窗口锁死，脱层从源头断——包胶，是温度的艺术。
小结
汽车制动防尘罩的材料选择，是一次判断力的练习，练多了自然就准，也欢迎转给需要的同事。
The dust cover delaminated and let in sand after just three months, and the brake components wore grooves. The material selection for the brake dust cover was missed, and rework is more expensive than buying the material.
Conclusion first: Look at the brake dust shield, hardness, and bonding together.
The brake dust cover is the 'leather on the brake parts': it prevents dust, sand, and water.
The material should have appropriate hardness, strong adhesion, and good resilience.
Conclusion first: SEBS-based TPE is mainstream. For overmolded parts that need strong bonding, use high-adhesion formulations or TPV.
A 10-degree increase in hardness changes the hand feel by one level; a deviation of one level in hardness changes the entire assembly feel—Shore A 50-70 is determined according to assembly conditions, and the hardness serves as the anchor point for the dust cover.
The brake dust cover is a 'functional part': if it fails to block dust, sand gets into the brake components. Choosing the right material ensures functionality—functional parts, don't skimp on material costs.
Why TPE Wins: Hardness Can Be Adjusted Freely, No One Beats Its Rubber Coating
Reasons for using TPE for the brake dust cover: hardness is adjustable, coating process is mature, rebound is good, cost is controllable — altogether, these four reasons make it suitable for a dust cover.
Hardness is key: too hard makes assembly difficult, too soft collapses. Shore A hardness is determined according to assembly conditions.
Delamination of the overmold is the death sentence for overmolded parts. The peel strength should be written into the acceptance criteria according to the standard——TPE over metal or nylon cores will delaminate if the peel is not strong after prolonged use.
It tests three operating conditions: friction, temperature, and brake fluid
Friction conditions: friction dust from brake components. Wear resistance and dust resistance data need to be tested — wear through the dust cover, and dust enters the brake components.
Temperature conditions: Brake components heat up. Temperature resistance is tested according to the actual temperature — if the temperature is insufficient, the dust cover will soften.
Medium conditions: brake fluid, oil contamination. The resistance to the medium needs to be tested—liquid swelling, dust protection failure.
TPE or Rubber: Explained Clearly in One Table
| Dimension | TPE (SEBS-based) | Rubber |
|---|
| Hardness | A40-80 Adjustable | Adjustable |
| Encapsulation bonding | Mature | Needs to be handled |
| rebound | Adjustable | Good |
| Molding | injection molding | Vulcanization |
| Cost | Low | Medium-high |
| Batch | Stable | Highly volatile |
Table reading: Rubber has good rebound but involves many processes and batch variations; TPE is efficient, with stable batches and mature overmolding — for mass production, TPE is the mainstream.
High-elasticity scenarios (frequent stretching), high rebound TPE formulation — choose according to function.
Three critical issues: hardness fluctuation, delamination, blistering
Pitfall 1: Hardness drift. Hardness fluctuates between batches—batch reports are more valuable than the grade name.
Pitfall 2: Coating delamination. Coated parts delaminate after long-term use—perform peel strength testing and include it in the acceptance criteria.
Pitfall three: Resistance to media leakage testing. Formulating brake fluid expansion—resistance to media data must be tested.
Check these three accounts upon arrival: hardness, peel, and media resistance
Three questions: According to what standard is the hardness, what is the peeling strength, and under what conditions is it resistant to media? One test: sample according to actual assembly—three questions and one test, the supplier's details are clear.
Encapsulation verification must be tested in practice: peeling and bending. In practical tests, the hardest is delamination once, which leads to a lot of rework.
Making sample retention a habit: retain samples for each batch and re-test hardness and adhesion by batch. When changing materials for a batch, compare first before scaling up — stable batches lead to fewer customer complaints.
Overmolded window locked: mold temperature, material temperature, holding pressure
Three-parameter lock for overmolding window: mold temperature, material temperature, holding pressure — the three parameters ensure the overmold is firm, while delamination often occurs when the temperature window is not correctly identified.
Mold temperature affects bonding: If the mold temperature is too low, bonding is not strong. Adjust according to the recommended value in the formula.
Material temperature affects flow: if the material temperature is too high, it will degrade and discolor, so control it according to the grade's recommended window.
Holding pressure affects density: insufficient holding pressure causes surface sink marks, adjusted according to part shape.
| Coating parameters | Window | Influence |
|---|
| Mold temperature | According to the recipe | Bonding strength |
| Material temperature | By brand | Flow/Degradation |
| Pressure holding | By item | Density |
| Cooling | By wall thickness | Dimensional stability |
Table 2 reading: Overmolded four parameters, lock it to be stable. Delamination is mostly due to not finding the right temperature window.
| Material specifications | Requirement | Explanation |
|---|
| Hardness | A50-70 | Tactile assembly |
| Peel strength | According to the standard | Tightly coated with rubber |
| rebound | ≥50% | Functional component |
| Media-resistant | According to the actual situation | Does not expand |
Table 3 reading: The four indicators are the health check chart of the dust cover. Hardness is 10 degrees, and the hand feel is one grade worse.
Different interference fits require different hardness levels. Read the data according to the actual assembly — hardness A50-70, rebound ≥50%. Only when assembled correctly will the hardness not be off.
Supplier of brake dust covers, ask four questions: what system, what is the peel strength, what standard is the hardness based on, and will changes be notified. After asking these four questions, the details are clear — asking the right questions is more useful than haggling over the price.
During proofing, simulate the continuous production of the encapsulation once: temperature accumulates, and the window will drift.
After continuous operation, single pieces are more stable — simulating continuously is more comprehensive than only looking at single pieces.
Loading and running brake tests, considering high temperature and friction together — the actual vehicle brakes are only released after passing batch tests. The cumulative temperature window during continuous production will drift, so continuous conditions are first simulated.
Cologne Customer Case: Bulk Delamination of Coating, Adjusting Parameters to Replicate Benchmark
At a car parts factory in Ma'anshan, brake dust cover overmolded parts were delaminating in large quantities, and the rework rate remained high. Kolon collaborated to adjust the injection molding parameters (mold temperature/material temperature/holding pressure), restoring the tactile rebound to match the sample, and the delamination problem disappeared. The parameter window was locked, stopping delamination at its source—overmolding is the art of temperature.
Summary
The material selection for car brake dust shields is an exercise in judgment; the more you practice, the more accurate you naturally become. Colleagues who need this are also welcome to share it with them.
