O型圈用三个月就漏油，机器停着等配件。O型圈密封和耐介质没选对，一颗小圈坏整台设备。
一颗小圈漏三个月，整台设备停
O型圈是“密封耐压的件”：密封、耐压、耐介质。材料要密封好、耐压、耐介质——结论先给：静态 O 型圈用 TPE 是主流；动态工况，橡胶（NBR/EPDM）留。
O型圈最大的坑：一个图便宜，一个图省心。便宜是暂时的，省心是长久的——用途，是 O 型圈的分界。
O型圈是功能件：泄漏、老化都是问题。材料选对，设备才稳——功能件，别省料钱。
O型圈为什么偏向 TPE
O型圈用 TPE 的理由：密封可做、成本可控、效率高、可回收——四条合起来，适合静态 O 型圈。
密封是核心：密封防漏。密封测试写进验收——泄漏，就是问题。
耐压不能省：压力工况。耐压测试写进验收——挤破，就是问题。
静态动态介质，三道关
静态工况：固定密封。密封数据要验——泄漏，就是问题。
动态工况：往复运动。耐摩数据要验——磨损，就是问题。
介质工况：接触介质。耐介质数据要验——溶胀，就是问题。
TPE 还是橡胶？O型圈一表
| 维度 | TPE | 橡胶 |
|---|
| 密封 | 可做 | 好 |
| 耐压 | 可做 | 好 |
| 动态 | 一般 | 好 |
| 成本 | 中 | 中高 |
| 效率 | 注塑 | 硫化 |
| 用途 | 静态 | 动态 |
表格读法：橡胶动态耐压好但贵；TPE 成本低、效率高——静态 TPE，动态橡胶。
按工况选：动态橡胶，静态 TPE。
O型圈验收：密封耐压两笔账
| 项目 | 方法 | 标准 |
|---|
| 密封 | 泄漏测试 | 无漏 |
| 耐压 | 压力测试 | 达标 |
| 耐介质 | 浸泡测试 | 无胀 |
| 硬度 | 计测 | 达标 |
表格读法：四项验收下来，省心才作数——耐压、耐介质、压变、回弹，静态动态分开算。
用途，是 O 型圈的分界。
静态动态混选，三个坑
坑一：静态动态混选。静态用廉价料凑合，动态往复件照样漏油——按工况选。
坑二：耐介质漏测。溶胀——耐介质测试，必测。
坑三：密封虚标。泄漏——密封按实测验收。
选O型圈料先分清动静
三问：静态还是动态、压力多少、介质是什么。一验：实际工况实测——三问一验，供应商底细清楚。
工况验证要先行：静态密封还是动态往复，先分清楚再选料。先定工况，再谈价格——用途，是 O 型圈的分界。
留样要成习惯：每批留样，密封耐压按批次复测。批次换料先对比再放量——批次稳，客诉少。
O型圈：老问题新对策，一表对照
| 现象 | 原因 | 对策 |
|---|
| 泄漏 | 密封不足 | 调硬度档 |
| 挤破 | 耐压不足 | 换耐压料 |
| 溶胀 | 耐介质弱 | 换耐介质料 |
| 磨损 | 动态不耐摩 | 换橡胶 |
| 批次漂移 | 配方波动 | 锁窗口 |
静态O型圈主流 Shore A 70-80，压缩量卡在15%-25%才不泄漏。 压超30%回弹不回来，长期受压件压缩永久变形别过30%（70℃×22h）——沟槽里的密封靠这档硬度兜。
静态用TPE免硫化、动态留NBR/EPDM，别拿一个料打天下。 TPE注塑成型快、边角料可回收，橡胶耐往复耐磨但要硫化——静态选TPE提效率，
动态磨损工况才回到橡胶。
O型圈泄漏先别怪料，先查沟槽尺寸和润滑兼容。 沟槽偏小挤坏、润滑剂不相溶胀，都是装配端的事；装配测试做过，再回头谈配方。
O型圈验收三件套：无泄漏测试、介质浸泡24h、硬度复测。 静态件按沟槽尺寸做装配核，动件加往复耐磨——一项不过不放行。
硬度锁在±3A内、-40℃弯折不断，O型圈装车一年回弹如初。 每批留样复测压变与硬度，批次换料先对比再放量。
O型圈沟槽尺寸按内径核，润滑剂兼容性单独做溶胀试。 沟槽偏小挤坏、油不相溶胀，装配端没核就换料白换，静态件压缩量 15%-25% 兜住密封。
动件加往复耐磨、静件测无泄漏，硬度锁 ±3A 内。 -40℃ 弯折不断，压变 70℃×22h 不过 30%，每批留样复测压变与硬度再放量。
批次换料先小批对比再放量，压变和硬度随批走。 每批留样复测压变与硬度，沟槽装配核过再谈配方，动件往复耐磨单独加测。
静态件压变是寿命线，长期受压别过三成。 沟槽内径核润滑剂兼容单独做，动件往复耐磨静件无泄漏，
硬度锁窄窗低温弯折不断，每批留样压变加硬度。
O型圈每批留样复测压变与硬度，批次换料先小批对比。 沟槽尺寸和润滑兼容先核，动件加往复耐磨，静件压变别过三成。
科隆客户案例：硬度批次漂移，小批试产过低温弯折
合肥一家工业设备厂，O型圈硬度批次漂移，手感忽软忽硬。科隆配合小批试产验证后再放量，硬度稳定，-40℃ 低温弯折一次通过。小批试产，把硬度锁死在放量前——批次漂移，先看配方窗口。
小结
O型圈的选型，工况先定，耐压再测，一个图便宜一个图省心，用途是分界。
三行说清我们是谁：
改性能——改性热塑性弹性体、改性尼龙（PA6 / PA66 / PA46 / PA11 / PA12 / PA6T / PA9T 及尼龙合金）、改性 PPO / PPS；
有货源——各大化工巨头尼龙树脂、副牌料、大包料现货；
给判断——什么件，用什么料。
- 批次：第 13 批｜TI1
- 主关键词：O型圈；次关键词：O型圈TPE、O型圈密封、O型圈耐压、O型圈材料
- 摘要：O型圈用TPE还是橡胶？一个图便宜，一个图省心。密封、耐压、选型三张表一次讲清。
- 更新时间：待定
The O-ring leaked oil after just three months, and the machine is idle waiting for parts. The O-ring's sealing and medium compatibility were not chosen correctly, and one small ring can ruin the entire piece of equipment.
A small seal leaks for three months, and the entire device stops
O-rings are 'components that are sealed and pressure-resistant': sealing, pressure-resistant, and resistant to media. The material must seal well, be pressure-resistant, and resistant to media — conclusion first: for static O-rings, TPE is mainstream; for dynamic conditions, rubber (NBR/EPDM) is retained.
The biggest pitfall of O-rings: one picture is cheap, another picture is worry-free. Cheap is temporary, worry-free is long-lasting—the usage is the dividing line for O-rings.
O-rings are functional components: leakage and aging are both problems. Choosing the right material ensures equipment stability—don't skimp on material costs for functional parts.
Why do O-rings tend to favor TPE?
Reasons for using TPE for O-rings: sealing is feasible, costs are controllable, efficiency is high, and it is recyclable—together, these four make it suitable for static O-rings.
Sealing is key: sealing prevents leaks. Sealing tests are included in acceptance criteria—leaks are problems.
Pressure resistance cannot be neglected: pressure conditions. Pressure resistance testing should be included in the acceptance—if it bursts, it’s a problem.
Static and dynamic media, three barriers
Static condition: fixed sealing. Sealing data needs to be checked — leakage is the problem.
Dynamic working condition: reciprocating motion. Wear resistance data need to be tested—wear is the issue.
Medium conditions: Contacting medium. Resistance data must be verified—the swelling, that's the problem.
TPE or rubber? O-ring chart
| Dimension | TPE | Rubber |
|---|
| Seal | Can do | Good |
| Pressure-resistant | Can do | Good |
| Dynamic | general | Good |
| Cost | middle | Medium-high |
| Efficiency | injection molding | Vulcanization |
| Purpose | Static | Dynamic |
Table reading: Rubber has good dynamic pressure resistance but is expensive; TPE is low-cost and efficient — static TPE, dynamic rubber.
Choose according to operating conditions: dynamic rubber, static TPE.
O-Ring Acceptance: Two Accounts of Seal Pressure Resistance
| Project | Method | Standard |
|---|
| Sealing | Leakage Test | No Leakage |
| Pressure Resistance | Pressure Test | Up to Standard |
| Medium Resistance | Soaking Test | No Swelling |
| Hardness | Measurement | Up to Standard |
Table Reading Method: After four acceptance items, only when everything is satisfactory can it be counted—Pressure resistance, medium resistance, compression set, rebound; static and dynamic are calculated separately.
Use is the dividing line for O-rings.
Static and Dynamic Mixed Selection, Three Pitfalls
Pitfall One: Mixing static and dynamic. Using cheap material for static fits, while dynamic reciprocating parts still leak oil—choose according to working conditions.
Pitfall Two: Medium resistance untested. Swelling—medium resistance test must be conducted.
Pitfall Three: Overstated sealing. Leakage—sealing must be accepted based on actual measurement.
Select O-ring Material According to Static or Dynamic
Three Questions: Static or dynamic, pressure level, and medium type. One Test: Test actual working conditions—three questions and one test make the supplier’s details clear.
Working condition verification should be done first: static sealing or dynamic reciprocating, clarify first, then select material. Determine working conditions first, then discuss price—use is the dividing line for O-rings.
Make sample retention a habit: retain samples from each batch, and retest sealing pressure resistance by batch. When changing material batches, compare first before mass production—stable batches result in fewer customer complaints.
O-rings: Old Problems, New Countermeasures, a Comparison Table
| Phenomenon | Cause | Countermeasure |
|---|
| Leakage | Insufficient Sealing | Adjust Hardness Setting |
| Extrusion | Insufficient Pressure Resistance | Replace with Pressure-Resistant Material |
| Swelling | Weak Medium Resistance | Replace with Medium-Resistant Material |
| Wear | Dynamic Not Abrasion-Resistant | Replace Rubber |
| Batch Drift | Formulation Fluctuation | Lock Window |
The mainstream Shore A hardness of static O-rings is 70-80, and the compression should be kept at 15%-25% to prevent leakage. If compressed over 30%, it won't rebound. For components under long-term compression, permanent deformation should not exceed 30% (70°C × 22h) — the seal in the groove relies on this hardness range.
Use TPE for static applications without vulcanization, and keep NBR/EPDM for dynamic ones. Don't try to use one material for everything. TPE injection molding is fast and scraps can be recycled, while rubber is wear-resistant under reciprocating motion but requires vulcanization—choose TPE for static applications to improve efficiency.
Rubber only returns under dynamic wear conditions.
Don't blame the material first if the O-ring is leaking; first check the groove dimensions and lubricant compatibility. If the groove is too small and gets crushed, or if the lubricant is incompatible and causes swelling, these are assembly issues; assembly tests should be done first, then you can talk about the formulation.
O-ring acceptance three-piece set: leak-free test, 24-hour medium soaking, hardness retest. Static parts are assembled and checked according to groove dimensions, while moving parts are additionally tested for reciprocating wear resistance — nothing is released if any item fails.
Hardness is locked within ±3A, does not break when bent at -40℃, and the O-ring rebounds like new after being installed for a year. Each batch has sample retests for compressive deformation and hardness, and when changing material batches, a comparison is made before mass production.
O-ring groove dimensions are based on the inner diameter, and lubricant compatibility is tested separately for swelling. If the groove is too small, it gets crushed; if the oil is incompatible, it swells. If the assembly end doesn’t match the inner diameter, changing the material is pointless. The compression of static parts should be 15%-25% to accommodate the seal.
The moving parts are enhanced with reciprocating wear resistance, and the stationary parts are tested to ensure no leakage, with the hardness locked within ±3A. It does not break when bent at -40℃, and compression set at 70℃ for 22 hours does not exceed 30%. Samples from each batch are retained for re-testing compression set and hardness before mass release.
For batch material changes, first compare small batches before scaling up; compression variation and hardness follow each batch. Keep samples from each batch to retest compression variation and hardness; review groove assembly before discussing the formula; additional testing is done individually for wear resistance of reciprocating parts.
Static part compression deformation is the life line, long-term compression should not exceed thirty percent. Lubricants compatible with groove inner diameter are handled separately, moving parts are reciprocally wear-resistant, and static parts have no leakage.
The hardness lock narrow window does not break under low-temperature bending, and each batch retains samples for compression deformation and hardness increase.
For O-rings, each batch should retain samples to retest compression set and hardness; when changing materials between batches, first compare with a small batch. Groove dimensions and lubrication compatibility should be verified first; moving parts add reciprocating wear tests, and for stationary parts, compression set should not exceed 30%.
Cologne Customer Case: Hardness Batch Drift, Low Temperature Bending in Small Batch Trial Production
An industrial equipment factory in Hefei experienced batch-to-batch fluctuations in the hardness of O-rings, with the feel sometimes soft and sometimes hard. Cologne coordinated a small-batch trial production for verification before scaling up, during which the hardness was stable and passed the -40°C low-temperature bend test in one go. In small-batch trial production, the hardness was locked before scaling up—batch-to-batch fluctuations; first, check the formulation window.
Summary
The selection of O-rings starts with determining the working conditions, then testing the pressure resistance. One figure saves money, another figure saves trouble; the purpose is to distinguish.
Explain who we are in three lines:
Performance modification—modified thermoplastic elastomers, modified nylon (PA6 / PA66 / PA46 / PA11 / PA12 / PA6T / PA9T and nylon alloys), modified PPO / PPS;
In stock—nylon resins from major chemical giants, secondary grade materials, bulk materials available;
Guidance—what part, use what material.
- Batch: 13th batch｜TI1
- Main keyword: O-ring; secondary keywords: O-ring TPE, O-ring sealing, O-ring pressure resistance, O-ring material
- Summary: Use TPE or rubber for O-rings? One picture shows cost-saving, another shows peace of mind. Sealing, pressure resistance, and selection tables explained at once.
- Update time: To be determined
