液冷这件事，在这两年从"数据中心的可选项"变成了"AI 机柜的必选项"。
原因很简单：单柜功率上去了，风冷压不住。
而液冷系统里，除了金属冷板和水泵，剩下的管路、快接头、支架、护套——有相当一部分可以换塑料件。
其中最能体现材料功力的一块，是快接头。
开篇先讲个现场
去年下半年去参观了一个新建的智算中心。机房里最震撼的不是成排的机柜，是机柜上方那些蓝色的粗管路——冷却液在里面循环，把热量源源不断带走。陪同的运维负责人说了一句让我记到现在的话：这套系统里最怕坏的不是一个服务器，是一个快接头，它坏了漏的不是水，是停在机房里的几千万。
AI 数据中心把液冷从“可选项”变成了“标配”，也把液冷用塑料件的要求抬到了前所未有的高度。传统机房漏水了关机检修，算力中心漏液就是事故，这里面的材料逻辑完全不同。
这篇就按算力中心的场景重新讲液冷选料。先盘点液冷系统里有哪些塑料件，各自的风险等级；然后重点拆快接头——整个系统里最挑料的一块；再讲冷板式和浸没式对材料的差异化要求，前者看水化学，后者看氟化液相容性，是两条完全不同的路。
阻燃是机房里的硬约束，单独一节。最后五个坑加边界。做液冷快接头、分液器、管路的企业，这篇按需取用。
一、液冷系统里有哪些塑料件
先把位置列清楚，再谈选料。
| 部位 | 材料方向 | 核心要求 |
|---|
| 冷却液软管 | PA12 / PA612 / PA11 | 耐水解、耐弯折 |
| 快接头本体 | PA12、PA612（增强） | 尺寸精度、耐水解、插拔寿命 |
| 冷板框架 / 固定件 | PA66-GF / PA6T-GF | 刚性、耐温、尺寸稳 |
| 分水器 / 歧管 | PA12-GF / PA66-GF | 耐压、耐水解、尺寸 |
| 风扇支架 | PA66-GF30 | 刚性、抗振、成本 |
| 理线件 / 护套 | 增韧 PA6 / PA12 | 韧性、阻燃 |
| 机柜内部结构件 | 阻燃 PA66-GF | V0、刚性 |
这张表里有一个明显规律：
碰冷却液的件往长碳链走，不碰冷却液的件可以留在 PA66。
分界线就是"接不接触介质"。 这条线画清楚了，选料范围立刻缩小一半。
二、快接头：液冷系统里最挑料的一块
快接头的要求，比其他件多四条。
① 尺寸精度。 密封靠配合尺寸。这也是液冷件要低吸水率材料的根本原因——吸水涨 0.1mm，密封就可能失效。
② 插拔寿命。 服务器维护要反复拆装，插拔次数是硬指标。锁止结构要有足够的韧性。
③ 长期受力。 卡扣、弹簧座长期处于应力状态，要看蠕变。
④ 无滴漏。 这是最特殊的一条——服务器机房里，漏一滴液体的代价远高于一个件本身的成本。
这四条叠加起来，答案基本指向：PA12 或 PA612 + 增强体系。
| 方案 | 优势 | 代价 |
|---|
| PA12 | 吸水率最低、耐水解最好、尺寸最稳 | 价格最高 |
| PA612 | 吸水率低、性价比更均衡 | 刚性略低 |
| PA66 + 耐水解体系 | 成本低、强度好 | 吸水率高，长期尺寸与水解风险大 |
| PPS / PPA | 耐温、耐化学最好 | 成本高、脆性偏大 |
还有一个实操建议：快接头的打样要连"对配件"一起验。
单测一个接头看不出问题，必须和对应的插座、密封圈一起做插拔和密封测试。装配尺寸链里任何一个件换了，密封表现都可能变。
在快接头上，我们一般不建议用 PA66。 不是不行，是"长期尺寸稳定"这一项在服务器场景里权重太高——一次渗漏的事故成本，远超用长碳链贵出来的那部分料钱。
一句话判断：液冷快接头选料，先问"这个件要不要做到十年不漏"，答案就出来了。
三、冷板式与浸没式：要求不一样
现在主流是两条路线，材料要求差别很大。
冷板式液冷
冷却液在冷板内循环，不直接接触电子元件。
介质：多为去离子水或水-乙二醇- 材料重点：耐水解 + 低吸水 + 尺寸稳定- 材质方向：PA12 / PA612 为主
这里和电池液冷的逻辑几乎一致，只是温度更低（一般 40-60℃），对耐温要求低一些，但对洁净度和离子析出更敏感。
温度低不等于要求低。 很多客户会想"冷板式只有 50℃，是不是可以用便宜一点的料"。答案是不行——去离子水的电导率要控制得很低，材料一旦有离子析出，整个回路的电导率就上去了。
所以冷板式选料，不能按"温度低所以宽松"来推。
还有一个容易忽略的位置：管路与冷板的接口。
这个位置同时有金属（冷板）和塑料（接头），还有密封面。线膨胀系数差异 + 长期温度循环，会让密封面的压力发生变化。
所以这个位置的塑料件，除了低吸水，还要看在 -20℃ 到 60℃ 循环下的尺寸稳定性。实验室常温测出来的配合尺寸，和机房跑了一年之后的配合尺寸，可能不是一回事。
去离子水有一个特殊要求：不能有离子析出。 冷却液的电导率要控制得很低。选料时要问材料的离子析出情况，这一条在冷板式系统里比在汽车液冷里更重要。
浸没式液冷
整个服务器浸在液体里，介质是氟化液或矿物油。
这一路对材料的要求完全不同——核心不是水解，是相容性。
要问的是：
| 问题 | 为什么重要 |
|---|
| 材料在氟化液里会不会溶胀？ | 溶胀会改变尺寸，影响密封和结构 |
| 会不会析出添加剂？ | 析出物污染介质，影响绝缘和换热 |
| 长期浸泡后力学性能保持如何？ | 需要浸泡试验数据 |
| 会不会影响介质本身的性能？ | 双向影响，都要评估 |
浸没式液冷选料，必须做浸泡试验，不能靠经验推。 因为氟化液的成分差异很大，不同供应商的液体对同一种材料的影响可能完全不同。
四、阻燃：机房里的硬约束
数据中心是密集型电气场所，阻燃要求不会因为"液冷"而放松。
机柜内部塑料件：UL94 V0 起步，很多场合要求无卤- 靠近线缆和电气件的结构件：同时看 GWIT- 长期温度虽不高，但要求低烟、低毒（机房有人工作环境）
注意一个组合难点：液冷件要低吸水，又要阻燃。
长碳链尼龙本身吸水低、韧性好，但阻燃改性难度比 PA66 大——加阻燃剂会影响流动性和韧性。同时要求"耐水解 + 低吸水 + V0"的件，配方难度是三个需求叠加的。
这类件最好在设计早期就把要求提全，不要先按结构选完料，再回头加阻燃。
还有一条：线缆附近的件要看灼热丝。
机房内部线缆密集，短路时的热源温度很高。GWIT 考的就是这件事：热源接触会不会把件点燃。
如果件只在 UL94 上做了功课，GWIT 没测，整机安规阶段很可能要返工。 这两项建议在选料时就一起提要求，别等送检前才发现。
快接头为什么是最挑料的位置
液冷系统里，快接头被反复点名为最挑料的位置，原因值得展开说。第一，它是全系统温差最大的位置，插拔瞬间冷热交变集中在这里。第二，它是密封副，密封面的尺寸稳定性直接决定漏不漏，吸湿变形在这里没有容忍度。
第三，它是运动副，插拔次数按千次计，磨损和蠕变叠加考核。第四，它是应力集中点，卡扣结构加残余应力，环境应力开裂在这里高发。四条挑战叠加，快接头选料的容错率是全系统最低的，其他位置的选型错误可能三年才暴露，快接头的错误半年就上门。
所以给做快接头的团队一个排序建议：宁可在外壳和管路上省，也别在快接头省，这里的每一分料钱都是最便宜的保险。
五、五个坑
坑 1：液冷管路用 PA66。 和电池液冷同一个坑，机理相同。
坑 2：快接头忽略长期尺寸。 快接头的失效多数是"渗"，不是"断"。尺寸稳定比强度重要。
坑 3：把冷板式和浸没式当一套要求。 前者看水解和洁净度，后者看相容性，两条路线。
坑 4：忘了离子析出。 冷板式用去离子水，材料析出会抬高电导率，影响系统。
坑 5：忽略装配与维修工况。 液冷件会被反复拆装，插拔寿命和锁止结构的疲劳必须一起验。
另外，液冷件的老化验证要包含"介质浸泡 + 温度循环"的组合工况。 只做单一条件（比如只泡不循环），测不出界面疲劳。
六、边界
| 件 | 结论 | 说明 |
|---|
| 冷板本体 | 不适合 | 需高导热金属（铜/铝） |
| 高压水泵叶轮 | 需谨慎 | 高速旋转 + 耐水解双要求，可用 PPS/PA12-GF |
| 长期 >120℃ 液冷件 | 需谨慎 | 换 PA1010 或复合方案 |
| 浸没式结构件 | 先做相容性试验 | 不能直接套用冷板式结论 |
| 强酸碱介质 | 不适合 | 需专门耐化学材料 |
行业里的一条实感
液冷询盘这两年变化很明显。
前两年客户问的是"液冷要不要做"，今年问的是"介质是哪一类"。
这个变化说明行业已经从"讨论方向"进入"落地选型"阶段了。而落地阶段，问法就越具体：
走的是去离子水、水-乙二醇，还是氟化液？- 温度是 45℃ 还是 90℃？- 是快接头还是管路本体？
这四个信息（介质、温度、部位、洁净度要求）给全了，方向基本就能定。
我们遇到最多的一个误区是：客户把"冷板式"和"浸没式"混着说。 这两种的介质、温度、材料要求都不同，混着问就会得到两套互相矛盾的答案。
所以我们接液冷询盘，第一句一定先问：是冷板式还是浸没式？ 这一句没问清，后面的推荐都是无效的。
读者追问两则
追问一：氟化液和去离子水两套系统，材料能通用吗？ 大体不能。冷板式走水基介质，考察水解和阻菌；浸没式走氟化液，考察溶胀和增重，氟化液对部分塑料有明显的渗透溶胀效应，水基系统里表现优秀的牌号在氟化液里可能增重超标。
两套系统的材料清单要分开维护，唯一可复用的是阻燃和机械框架。选型前先确认自己的件泡在哪种介质里，这一步错了后面全错。
追问二：机房改造项目怎么评估原有塑料件的兼容性？ 分三步：先查原件的材质证明，确认基材和改性体系；再按新工况列差异表，介质、温度、阻燃要求逐项对比；最后对有差异的位置取样做兼容性浸泡试验，短周期两周就能筛出明显问题。
最忌讳的是只看外观没发现问题就直接沿用，液冷兼容性的坑多数藏在件内部，等渗出来就晚了。
给快接头供应链再补一句交期视角的话：算力中心的建设节奏以月计，液冷件的交付窗口经常被压到极限。选料的时候，把候选牌号的备货周期问清楚——主流大厂的常备牌号四周内可交付，冷门高温牌号可能要排十二周以上。
同样的性能，交付确定性差一倍的项目风险完全不同。把交期作为选型权重之一，是算力时代供应链的必修课，这一课的电费，比想象中贵得多。
液冷件供应商四问
液冷塑料件选供应商，问四个问题比看资质墙有用。一问介质验证：你们的浸泡验证用什么介质，氟化液和水基是不是分开设的工况，混用一套数据的直接排除。二问密封副工艺：密封面的模具和注塑管控怎么做，有没有专门的密封带质量标准，答不出具体动作的要警惕。
三问插拔测试：按什么频次做、多少次一批、失效判据是什么，快接头的核心寿命证据就在这里。四问变更通知：配方或模具变更多久通知客户，有没有书面流程，液冷件最怕静默变更，一次悄悄换料可能就是机房事故。
四个问题的回答质量，比规模和价格更能预测合作体验。问完不放心的话，要一次小批试用，快接头的信任是用插拔数据攒出来的。
再补一个运维视角的提醒：液冷系统上线之后的维护文档里，把每个塑料件的牌号、批次、更换记录写进资产台账。算力中心的服役期长达十年以上，这期间运维团队可能换了几轮，台账是唯一能把材料信息延续下去的载体。
我们见过改造项目翻出五年前的旧接头，没人说得清是什么料，只能整体更换，一轮下来多花的钱够建三套台账。材料信息也是资产，管好它，未来每次改造都省真金白银。
结语
AI 数据中心的液冷件，选料逻辑其实只有两句话：
碰冷却液的，走长碳链尼龙；不碰冷却液的，留在 PA66 体系。
再把"阻燃"和"介质相容性"两件事补上，方向就完整了。
补一句顺序： 先分"碰不碰介质"，再分"冷板式还是浸没式"，最后才谈具体牌号。三步的顺序不能反——反了，就会拿冷板式的结论去套浸没式，白做一轮。
最容易出错的地方，永远是快接头——因为它要求的不只是"这个料能不能用"，而是"这个件十年后还能不能密封"。
The matter of liquid cooling has, over the past two years, changed from 'an optional feature for data centers' to 'a must-have for AI cabinets'.
The reason is very simple: the power of a single cabinet went up, and the air cooling couldn't keep up.
In the liquid cooling system, apart from the metal cold plate and the water pump, a significant portion of the remaining tubing, quick connectors, brackets, and sleeves can be replaced with plastic parts.
One part that best demonstrates the material skill is the quick connector.
Let's start with a live scene
In the second half of last year, I visited a newly built intelligent computing center. What was most shocking in the computer room was not the rows of server racks, but the thick blue pipes above the racks—the coolant circulates inside them, continuously carrying away heat. The operations and maintenance manager accompanying me said something that I still remember: the most feared thing in this system is not a server breaking down, but a quick connector; if it fails, what leaks out is not water, but tens of millions sitting in the computer room.
AI data centers have turned liquid cooling from an 'optional feature' into a 'standard configuration,' and they have also raised the requirements for using plastic components in liquid cooling to unprecedented heights. In traditional data centers, a leak leads to shutdown for maintenance, but a leak in a computing power center is an accident— the material logic here is completely different.
This article will retell the selection of materials for liquid cooling based on the scenario of a computing power center. First, we will inventory the plastic parts in the liquid cooling system and their respective risk levels; then we will focus on the quick connectors—the most demanding component in the entire system; finally, we will discuss the different material requirements for cold plates and immersion cooling. The former concerns water chemistry, while the latter concerns compatibility with fluorinated liquids—they are two completely different paths.
Flame retardancy is a hard constraint in the computer room, treated as a separate section. The last five pitfalls plus the boundaries. For companies that make liquid cooling quick connectors, manifolds, and pipelines, this article can be used as needed.
1. What plastic parts are there in the liquid cooling system
First list the locations clearly, then talk about material selection.
| Body part | Material direction | Core requirements |
|---|
| Coolant hose | PA12 / PA612 / PA11 | Hydrolysis-resistant, bend-resistant |
| Quick coupler body | PA12, PA612 (reinforced) | Dimensional accuracy, hydrolysis resistance, mating cycle durability |
| Cold Plate Frame / Fixtures | PA66-GF / PA6T-GF | Rigid, temperature-resistant, dimensionally stable |
| Water distributor / Manifold | PA12-GF / PA66-GF | Pressure resistance, hydrolysis resistance, dimensions |
| Fan bracket | PA66-GF30 | Rigidity, vibration resistance, cost |
| Cable management / Sheathing | Toughened PA6 / PA12 | Toughness, flame retardant |
| Cabinet internal structural components | Flame-retardant PA66-GF | V0, Rigidity |
There is an obvious pattern in this table:
Parts that come into contact with coolant should go to long carbon chains, while parts that do not come into contact with coolant can remain in PA66.
The boundary is whether to 'come into contact with the medium' or not. Once this line is clearly drawn, the range of material selection immediately shrinks by half.
2. Quick Connectors: The most picky component in a liquid cooling system
The requirements for the quick connector are four more than those for other parts.
① Dimensional accuracy. Sealing depends on the fit dimensions. This is also the fundamental reason why liquid-cooled components require materials with low water absorption—if water absorption causes a 0.1mm expansion, the seal may fail.
② Plug-in and plug-out lifespan. Servers require repeated assembly and disassembly for maintenance, so the number of plug-in and plug-out cycles is a key metric. The locking mechanism must have sufficient toughness.
③ Long-term stress. The buckle and spring seat are under stress for a long time, so creep needs to be considered.
④ No leaks. This is the most special requirement — in a server room, the cost of a single drop of liquid leaking far exceeds the cost of the component itself.
When these four factors are combined, the answer basically points to: PA12 or PA612 enhanced system.
| Plan | Advantage | Cost |
|---|
| PA12 | Lowest water absorption, best hydrolysis resistance, most dimensionally stable | Highest price |
| PA612 | Low water absorption rate, more balanced cost-performance ratio | Slightly low rigidity |
| PA66 Hydrolysis-Resistant System | Low cost, good strength | High water absorption, long-term dimensional and hydrolysis risk is high |
| PPS / PPA | Best in temperature resistance and chemical resistance | High cost, relatively brittle |
There is another practical suggestion: the sample of the quick connector should be inspected together with the 'matching parts'.
Testing a single connector alone cannot reveal problems; it must be tested for insertion, removal, and sealing together with the corresponding socket and sealing ring. If any component in the assembly dimension chain is changed, the sealing performance may also change.
For quick connectors, we generally do not recommend using PA66. It's not that it's impossible to use, but the 'long-term dimensional stability' factor is too important in server scenarios — the cost of a single leakage incident far exceeds the extra material cost of using a long-chain carbon PA66.
A one-sentence judgment: When selecting materials for liquid cooling quick connectors, first ask 'Does this part need to be leak-free for ten years?' The answer will be revealed.
3. Cold Plate Type and Immersion Type: Requirements Are Different
The current mainstream is two routes, with very different material requirements.
Cold plate liquid cooling
The coolant circulates within the cold plate and does not come into direct contact with the electronic components.
Medium: mostly deionized water or water-ethylene glycol. Key material points: hydrolysis-resistant, low water absorption, dimensionally stable. Material direction: mainly PA12 / PA612.
The logic here is almost the same as battery liquid cooling, except the temperature is lower (generally 40-60℃), so the temperature resistance requirement is somewhat lower, but it is more sensitive to cleanliness and ion deposition.
Low temperature does not mean low requirements. Many customers might think, 'The cold plate is only 50℃, so can we use cheaper materials?' The answer is no— the conductivity of deionized water must be kept very low. Once the material releases ions, the conductivity of the entire circuit will increase.
Therefore, when selecting materials for cold plate processes, one cannot justify it based on 'low temperature means loose fitting'.
There is another easily overlooked spot: the interface between the pipeline and the cold plate.
This position has both metal (cold plate) and plastic (joint), as well as a sealing surface. The difference in thermal expansion coefficients and long-term temperature cycling will cause the pressure on the sealing surface to change.
So for the plastic parts in this position, besides low water absorption, we also need to consider dimensional stability under cycles from -20°C to 60°C. The fitting dimensions measured at room temperature in the laboratory may not be the same as the fitting dimensions after running in the machine room for a year.
Deionized water has a special requirement: no ions should precipitate. The conductivity of the coolant must be kept very low. When selecting materials, one should inquire about the ion precipitation of the materials. This requirement is more important in plate-type cooling systems than in automotive liquid cooling.
Immersion liquid cooling
The entire server is immersed in liquid, with the medium being fluorinated liquid or mineral oil.
The requirements for materials along this path are completely different—the core is not hydrolysis, but compatibility.
The question is:
| Question | Why is it important? |
|---|
| Will the material swell in the fluorinating solution? | Swelling can change the dimensions and affect sealing and structure |
| Will the additives precipitate? | Precipitated substances contaminate the medium, affecting insulation and heat exchange |
| How are the mechanical properties maintained after long-term soaking? | Soaking test data is required |
| Will it affect the performance of the medium itself? | Both-way impact, both need to be assessed |
For immersion liquid cooling material selection, immersion tests must be conducted and cannot rely on experience. This is because the composition of fluorinated liquids varies greatly, and liquids from different suppliers may have completely different effects on the same material.
4. Fire Retardant: Hard Constraints in the Server Room
Data centers are high-density electrical environments, and flame retardant requirements will not be relaxed because of 'liquid cooling'.
Plastic parts inside the cabinet: starting from UL94 V0, many occasions require halogen-free. Structural parts close to cables and electrical components: also consider GWIT. Although the long-term temperature is not high, low smoke and low toxicity are required (since it is an environment where people work in the machine room).
Pay attention to a combined difficulty: liquid-cooled components need to be low in water absorption, and also flame-retardant.
Long-chain nylon itself has low water absorption and good toughness, but flame-retardant modification is more difficult than PA66 — adding flame retardants affects fluidity and toughness. At the same time, for parts that require 'hydrolysis resistance, low water absorption, and V0,' the formulation difficulty is the combination of these three requirements.
For this type of part, it is best to include all the requirements early in the design, rather than selecting the material according to the structure first and then going back to add flame retardancy.
There is one more point: the components near the cables need to be checked for hot wires.
The cables inside the computer room are dense, and the heat source temperature is very high during a short circuit. GWIT tests exactly this: whether contact with the heat source will ignite components.
If the part has only been tested according to UL94 and GWIT has not been measured, there is a high possibility of rework during the overall safety compliance stage. It is recommended to make these two requirements together when selecting materials, rather than discovering them just before sending for inspection.
Why is the quick joint the most selective spot for materials?
In liquid cooling systems, quick connectors are repeatedly singled out as the most demanding parts, and the reasons are worth elaborating. First, they are the locations with the greatest temperature differences in the entire system, where hot and cold changes are concentrated during insertion and removal. Second, they are sealing components, and the dimensional stability of the sealing surfaces directly determines whether there will be leaks; there is no tolerance for moisture-induced deformation here.
Third, it is a moving joint, with plugging and unplugging counted in thousands of times, and both wear and creep are assessed cumulatively. Fourth, it is a stress concentration point; the clip structure adds residual stress, making environmental stress cracking highly likely here. With these four challenges combined, the tolerance for material selection in quick connectors is the lowest in the entire system. Errors in selecting materials for other positions might only surface after three years, while errors in quick connectors show up within six months.
So here's a ranking suggestion for the team making quick connectors: it's better to save on the casing and pipes than to save on the quick connectors; every penny spent here is the cheapest form of insurance.
Five, five pits
Pitfall 1: Use PA66 for liquid cooling pipelines. Same pitfall as battery liquid cooling, the mechanism is the same.
Pitfall 2: Quick couplings ignore long-term dimensions. Most failures of quick couplings are 'leakage', not 'breakage'. Dimensional stability is more important than strength.
Pitfall 3: Treating the cold-plate method and the immersion method as the same set of requirements. The former focuses on hydrolysis and cleanliness, while the latter focuses on compatibility—they are two different approaches.
Pitfall 4: Forgetting ion precipitation. Cold plate systems use deionized water, and material precipitation can raise conductivity, affecting the system.
Pitfall 5: Neglecting assembly and maintenance conditions. Liquid-cooled components will be repeatedly disassembled, so the plug-in lifespan and the fatigue of the locking structure must be tested together.
In addition, the aging verification of liquid-cooled components should include the combined conditions of 'media immersion and temperature cycling.' Testing under a single condition (for example, immersion without cycling) cannot detect interface fatigue.
6. Borders
| piece | Conclusion | Explanation |
|---|
| Cold plate body | Not suitable | Requires high thermal conductivity metal (copper/aluminum) |
| High-pressure water pump impeller | Need to be cautious | High-speed rotation, requiring both hydrolysis resistance and durability, PPS/PA12-GF can be used |
| Long-term >120℃ liquid-cooled component | Need to be cautious | Replace PA1010 or use a composite solution |
| Immersed structural component | First conduct a compatibility test | Cannot directly apply cold-form conclusions |
| Strong acid and alkaline medium | Not suitable | Requires materials resistant to chemicals |
A real feeling in the industry
The inquiries about liquid cooling have changed significantly in the past two years.
A couple of years ago, clients asked 'Do we need to do liquid cooling?' This year, they ask 'What type of medium is it?'.
This change indicates that the industry has moved from the 'discussion direction' stage to the 'implementation and selection' stage. And in the implementation stage, the questions become more specific:
Is it going through deionized water, water-ethylene glycol, or fluorinated liquid? - Is the temperature 45℃ or 90℃? - Is it a quick connector or the main body of the pipeline?
Once these four pieces of information (medium, temperature, location, cleanliness requirements) are all provided, the direction can basically be determined.
The most common misconception we encounter is that clients mix up 'cold plate' and 'immersion.' The media, temperature, and material requirements for these two are different, and asking about them together will result in two sets of contradictory answers.
So when we receive an inquiry about liquid cooling, the first question must be: is it cold plate type or immersion type? If this question is not clarified, any subsequent recommendations are invalid.
Two Reader Inquiries
Follow-up Question 1: Can the materials be used interchangeably between the fluorination liquid system and the deionized water system? Generally, no. The cold plate type uses water-based media, focusing on hydrolysis and antibacterial properties; the immersion type uses fluorination liquid, focusing on swelling and weight gain. The fluorination liquid has noticeable permeation and swelling effects on some plastics, so grades that perform well in the water-based system may exceed the weight gain limit in the fluorination liquid.
The material lists for the two systems need to be maintained separately; the only reusable components are the flame retardant and mechanical framework. Before selecting components, first confirm which medium your part foam is in—if this step is wrong, everything that follows will be wrong.
Follow-up Question 2: How do we assess the compatibility of existing plastic parts in a data center renovation project? There are three steps: first, check the material certification of the original parts to confirm the base material and modification system; second, create a difference table according to the new working conditions, comparing each item such as medium, temperature, and flame-retardant requirements; finally, take samples from areas with differences for compatibility immersion tests, and obvious issues can be screened out in a short cycle of two weeks.
The biggest taboo is to just look at the appearance, find no problems, and use it directly. Most of the pitfalls of liquid cooling compatibility are hidden inside the components, and it will be too late once they leak out.
Add one more perspective on delivery schedules for the fast connector supply chain: The construction pace of computing centers is measured in months, and the delivery window for liquid-cooled components is often pushed to the limit. When selecting materials, make sure to ask about the stocking cycle of candidate grades—the commonly used grades from major manufacturers can be delivered within four weeks, while niche high-temperature grades may need to wait more than twelve weeks.
With the same performance, the project risk of delivering with half the certainty is completely different. Using delivery time as one of the selection criteria is a compulsory lesson for the supply chain in the computing era, and the electricity cost for this lesson is much higher than imagined.
Four Questions for Liquid Cooling Component Suppliers
When selecting suppliers for liquid-cooled plastic parts, asking four questions is more useful than looking at a wall of qualifications. Question one: medium validation—what medium do you use for immersion testing? Are fluorinated liquids and water-based ones tested under separate conditions? If a single set of data is used for both, discard it immediately. Question two: sealing component process—how do you control the mold and injection molding for sealing surfaces? Is there a specific quality standard for sealing? Be cautious if they cannot specify concrete actions.
Question three: insertion and withdrawal testing—how frequently is it done, how many cycles per batch, and what are the failure criteria? The core evidence of a quick connector’s service life lies here. Question four: change notification—how long in advance are customers notified of formula or mold changes, and is there a written process? Liquid-cooled components are most vulnerable to silent changes; quietly changing materials once could lead to a data center incident.
The quality of answers to these four questions predicts the cooperation experience more than scale or price. If you’re still unsure after asking, conduct a small trial batch; trust in quick connectors is built from insertion and withdrawal data.
One more reminder from an operations perspective: after a liquid cooling system goes online, record the grade, batch, and replacement history of each plastic part in the asset ledger. Data centers can be operational for over ten years, during which maintenance teams may rotate several times. The ledger is the only way to preserve material information over time.
We’ve seen renovation projects where old connectors from five years ago were found and no one could confirm the material, forcing a complete replacement—which cost enough to create three ledgers. Material information is also an asset; managing it properly saves real money during future renovations.
Conclusion
For AI data center liquid-cooled parts, the material selection logic boils down to two sentences:
If it contacts coolant, use long-chain nylon; if it doesn’t, stay within the PA66 system.
Add "flammability" and "medium compatibility," and the approach is complete.
One more note on the order: first determine "contact with medium or not," then "cold plate or immersion type," and finally discuss specific grades. Don’t reverse these steps—if you do, you’ll apply cold plate conclusions to immersion systems and waste a round of work.
The area most prone to mistakes is always the quick connector—because it requires not just "can this material be used," but "will this part still seal properly in ten years."
