190 家电电机与压缩机部件
家电电机的温度环境
冰箱压缩机、空调电机、洗衣机电机长期在 80-120℃ 下工作。
压缩机壳内温度可达 100-120℃，且长期不维护。这是家电里温度最高、维护最少的位置，对材料的热老化性能要求最高。
端盖与骨架的选材
电机端盖：走 PA66-GF25 或 BMC（团状模塑料），要耐热、阻燃、尺寸稳定。绝缘骨架：走 PA66-GF25 或 PBT-GF25，要耐热 130℃ 以上、阻燃 V-0、CTI ≥ 400 V。PBT 在骨架上优于 PA66——吸湿小、介电稳定。
现场还原：压缩机壳里的十年
2025 年 1 月，广东一家家电压缩机厂的装配车间，工程师指着流水线上的一台压缩机说：「这台机器关在冰箱里十年不坏，也算十年不歇——塑料件在里面，一次检修机会都没有。」
冰箱压缩机是家电里最封闭的工况：内部密封、冷冻油长期浸泡、绕组发热、冷媒环境，还有启动瞬间的电磁冲击。塑料件（端盖绝缘件、接线端子座、内部支架）装进去之后，十年免检——失效的形式不是「坏」，是「整机报废」。
这家厂上一代的一个坑：接线端子座用普通阻燃 PA66，五年后批量反馈压缩机启动电容失压——端子座在冷冻油加热的长期环境里蠕变，端子压紧力松弛，接触电阻上涨，启动电流带不动。
整改：端子座换低蠕变耐油阻燃牌，验证按「十年加速」走：热氧老化 5000 小时加油浸泡复合试验，蠕变数据按 10 万小时取。
压缩机行业的材料验证，逻辑上和电力金具类似：一次装机、终身免检、失效即整机。这类「封闭系统件」的选材哲学只有一条——把十年当一天来验。
压缩机内部件是特殊领域
冰箱压缩机内部有冷冻油和冷媒（R600a、R134a），塑料件要耐冷媒和冷冻油，还要耐 120℃ 高温。
这是非常特殊的工况，普通工程塑料全部出局。走 PPS、PAI 或专用耐冷媒 PA。这一块基本被进口料垄断。
耐热氧老化是核心
电机件长期高温 + 氧气，热氧老化是主要失效机理。PA66 不加耐热剂，120℃ 下 2000 h 强度就掉到 50%。
必须加抗氧剂 + 热稳定剂双件套，可达 5000 h 保持 80%。这是家电电机件选料的第一判据。
深一层：热氧老化——封闭系统里的慢刀子
聊压缩机件，热氧老化这个概念值得单独展开，因为封闭系统里的失效几乎全是它主导的。
热氧老化的机理：氧气（哪怕是密封系统里的残余氧）在温度催化下攻击高分子链，链断裂加交联同时发生——材料变脆、变硬、析出小分子。这个过程缓慢但单调：温度每高 10℃，速率翻倍，十年寿命的件，加速试验按这个规律折算。
压缩机里的热氧老化有三个放大器：冷冻油（油对某些塑料有萃取和溶胀作用，加速老化）、绕组热（端子座贴近绕组，局部温度比标称环温高 20-30℃）、还有冷媒（氟利昂类冷媒对部分塑料有增塑作用，R600a 体系的相容性要求和 R134a 不同）。
材料端的应对按优先级排：端子座和绕组贴近位用耐热氧老化专用牌（RTI 140 级加油相容体系），远离热源的结构件可用通用耐油牌；验证做「热氧加油浸」复合老化，单一工况的验证会高估寿命。
还有一条工程提醒：封闭系统件的失效没有预警——不像户外件有粉化变色这种「求救信号」，压缩机里的塑料件失效直接表现为整机异常。所以封闭系统的材料验证，要按「最坏假设全验」来做，用试验室的几千小时，换现场的十年沉默。
尺寸稳定与动平衡
电机转子动平衡精度要求高，端盖轴承室的尺寸稳定性直接影响噪音和寿命。
PA66 吸湿会涨，轴承室尺寸要留吸湿余量，或者走 PBT。
另外端盖与定子的配合要过盈或过渡配合，尺寸公差 ±0.05 mm，注塑精度要求高。
能效等级的倒逼
家电能效标准不断升级，电机效率每提高 1% 都要付出巨大努力。
这对塑料件的意义是：减少摩擦损失、减少振动、降低温升。
具体做法是高尺寸精度的轴承室、低摩擦的风扇叶、良好的散热设计。
材料在这个链条里是配角，但配角做不好会拖垮主角。
工程实测：4 条强制测试
测试1：热氧老化 120℃ 2000 h。加抗氧双件套 PA66 强度保持 80%，未加的降至 50%——电机件必加。
测试2：耐冷媒。PPS 在 R134a + 冷冻油 120℃ 下稳定，普通 PA66 溶胀——压缩机内部件走 PPS。
测试3：尺寸稳定。PBT 吸湿尺寸变化 0.1%，PA66 达 0.35%——轴承室优先 PBT。
测试4：阻燃 CTI。PBT-GF25 无卤阻燃 V-0 + CTI 500 V——骨架标准配置。
追问三连：采购最常问的三件事
一问：端盖和骨架怎么分料。 端盖贴着绕组发热区，走 RTI 140 级耐热牌；骨架（绕线骨架）直接接触漆包线和浸渍漆，要多验一项「耐漆包线漆和浸渍漆相容」——漆里的溶剂对塑料的攻击在固化残留期最强。两个位的温度和介质都不同，一张料单打天下是压缩机行业的老坑。
二问：尺寸稳定和动平衡为什么重要。 压缩机转速高（3000-6000 rpm），内部塑料件的微小变形都会传导为振动和噪音：转子护套、平衡块支架这些件的蠕变直接表现为整机振动超标。验证做热老化后动平衡复测——出厂动平衡合格不等于十年后合格，老化和蠕变会把平衡悄悄带走。
三问：能效等级倒逼了什么。 能效新规把压缩机的效率线年年抬高，塑料件的两个贡献点：轻量化（转子组件减重降惯量，启动能耗降）和低摩擦（含油耐磨体系降机械损耗）。能效档案里写着材料的名字——这一点很多整机厂还没意识到，先意识到的供应链先拿订单。### 算一笔材料账：封闭件的免检溢价
压缩机这类封闭系统件的材料账，结构上和开放件相反：材料费极小，失效代价极大，免检溢价是核心科目。
端子座这类内部件，单件材料成本不足 2 元，专用低蠕变牌贵 0.5 元。这 0.5 元的对价：把「五年后批量接触电阻漂移」的概率从行业已发生过的水平，压到接近零。
失效代价：压缩机不单独维修，坏即整机报废。按一台冰箱压缩机组的售后全成本（压缩机、冷媒、工时、上门）400 元计，故障率每高一个百分点，每百台机型的期望损失 400 元——是端子座全年材料差价的几十倍。
更结构性的账在品牌端：冰箱的质保期普遍十年起，压缩机的故障率直接挂靠在整机质保的财务模型上。材料档位的每一档升级，都在给十年质保的精算模型松绑。
封闭件供应链的特点也由这笔账决定：一旦定型，整机厂十年不换料、不轻易换供应商。对改性厂，这是长尾里最长的尾——单件利润薄，但一个定点吃十年。封闭件的市场竞争，拼的不是报价单，是十年加速验证的数据厚度。### 边界声明
| 工况 | 推荐材料 |
|---|
| 电机端盖 | PA66-GF25 耐热 |
| 绝缘骨架 | PBT-GF25 高 CTI |
| 压缩机内部件 | PPS 或耐冷媒专用料 |
| 冷却风扇 | PA66-GF30 |
| 耐热要求高 | PA66 + 抗氧 + 热稳定双件套 |
工程备忘
家电电机件量产前必须做 120℃ 热氧老化 + 耐冷媒 + 尺寸稳定三项。抗氧 + 热稳定双件套是标配，不加两年就脆。
实战案例：常见踩坑与正解
踩坑一：按常温物性表给家电电机件选料，没考虑长期工作温度。家电件长期在 60-90℃ 下工作，常温强度再高也会热老化失效。正解：拿热老化后的数据选料，PA66 在 80℃ 长期工作要选耐热氧老化牌号。踩坑二：为了降本把增强料换成未增强料，或者把 GF30 降到 GF15。家电电机件的玻纤含量是算出来的，不是拍出来的。正解：降玻纤含量必须重算蠕变和强度，不能凭经验。踩坑三：噪音和异响问题最后才查，发现是塑料件摩擦或松动。正解：家电的噪音投诉占比很高，塑料件的配合公差和自润滑要在设计阶段就定。
反向案例：端子座蠕变的五年账期
把前面那个端子座案例的时间线完整记一遍，它是封闭系统失效的标准样本。
2020 年压缩机改款，端子座从原供应商换到新供应商，牌号名义相同、配方体系不同——新料的阻燃体系换了，蠕变特性没人复核。当年出货正常，各项出厂测试全过。
2023 年起，售后端陆续反馈「冰箱不制冷」，比例低但逐年涨。拆机定位：端子座蠕变，端子压紧力衰减，接触电阻从毫欧级涨到欧姆级，启动电容回路异常。
2025 年整改完成：端子座换低蠕变牌，接触电阻做 5000 小时热老化后复测进标准，供应商体系审核加「关键参数变更报备」条款。
这五年的总账：售后赔付、品牌口碑、经销商信心，累计损失七位数；端子座本身的价差，每年不到十万。
压缩机厂的品质总监在复盘会上有个说法：「封闭系统件的失效，账期是五年起算的——五年前的采购决定，五年后由售后买单。」这句话后来被印在他们供应商大会的背景板上。
封闭系统的材料变更，审核的严格程度要按「整机报废」来定级，不是按「单件成本」来定级。
延伸判断：验证顺序不要搞反
家电电机件的验证有固定顺序，跳过前面的直接做后面的，等于白做。
第一步验证材料本身：力学、热学、阻燃、电气这几项，确认料号没选错。
第二步验证工艺窗口：同一批料在不同模温、不同保压下打出来的件，性能差异可能超过 20%，工艺窗口要跑出来。
第三步才做整机或整件验证：装到实际工况里跑寿命。很多人的顺序是反的——直接装机跑寿命，不合格了不知道是料的问题还是工艺的问题，于是反复换料，半年出不了结果。
把这三件事写成一张表发给供应商，比打十通电话有用——家电电机件的选型沟通成本，基本都花在这几项反复确认上。
补记：三个现场判断信号
信号一：整机振动噪音渐大。 内部塑料件蠕变或磨损，拆检转子和支架位，动平衡按老化后状态复测。
信号二：启动异常、电容回路失压。 端子座接触电阻漂移，整批按批次号排查，端子座料档复核，这是安全级信号。
信号三：冷媒回路异常加油色变化。 塑料件析出物污染系统，低析出牌替换是根治，过滤只是缓冲。### 验证顺序：三步走完再下单
第一步，验复合：热氧老化加油浸加冷媒相容，封闭系统的验证永远是复合工况。
第二步，验十年：蠕变和接触电阻按十年折算的加速条件取数，出厂合格不等于十年合格。
第三步，锁变更：关键参数（阻燃体系、填充体系）变更强制报备，封闭件的配方稳定性就是产品生命线。三步走完，封闭系统的免检承诺才有材料背书。
结语
样品寄出去之后——选料这件事，越早问越省事。
这类件的选料与试模，可以一起聊。
190 Appliance motors and compressor components
Temperature environment of household appliance motors
Refrigerator compressors, air conditioner motors, and washing machine motors operate long-term at 80-120°C.
Compressor housing temperature can reach 100-120°C and requires long-term maintenance. This is the hottest and least maintenance area among home appliances, requiring the highest thermal aging performance of materials.
Selection of end caps and frame materials
Motor end covers: use PA66-GF25 or BMC (bulk molding compound), which must be heat-resistant, flame-retardant, and dimensionally stable. Insulated frame: PA66-GF25 or PBT-GF25 must withstand heat above 130°C, flame-retardant V-0, CTI ≥ 400 V. PBT is superior to PA66 in terms of skeleton—low moisture absorption and stable dielectric.
On-site Replica: Ten Years Inside the Compressor Housing
In January 2025, in the assembly workshop of a home appliance compressor factory in Guangdong, an engineer pointed to a compressor on the assembly line and said, "This machine has been locked in a refrigerator for ten years without breaking, so it hasn't broken for ten years—the plastic parts are inside, and there's not even a chance for repair."
The refrigerator compressor is the most closed operating condition among home appliances: internal sealing, long-term soaking in refrigerant oil, winding heating, refrigerant environment, and electromagnetic shock at startup. After installing plastic parts (end cover insulators, terminal blocks, internal brackets), they are inspected for ten years—failure is not "fault," but "complete unit scrapping." A pitfall from the previous generation of
factory: the terminal block used ordinary flame-retardant PA66, and after five years, the mass report of compressor capacitor voltage loss — the terminal block creeps in the long-term heating environment of the refrigeration oil, the terminal tightening force loosens, contact resistance rises, and the starting current cannot be held.
Rectification: Replace terminal blocks with low-creep, oil-resistant, flame-retardant brands, validation follows "Ten-Year Acceleration": thermal oxygen aging for 5,000 hours of oil immersion composite test, creep data taken as 100,000 hours.
Material verification in the compressor industry is logically similar to electrical fittings: one-time installation, lifetime exemption from inspection, failure means complete unit. The material selection philosophy for these "closed system components" is simple—treat ten years as a day for testing.
Compressor internal components are a special field
Refrigerator compressors contain refrigerant oil and refrigerant (R600a, R134a), plastic parts must withstand refrigerant and oil resistance, and also withstand temperatures up to 120°C.
This is a very special operating condition, where all ordinary engineering plastics are eliminated. They use PPS, PAI, or specialized refrigerant PA. This area is basically monopolized by imported materials.
Thermal and oxygen aging resistance is the core .
Electrical components are subjected to long-term high temperature + oxygen, with thermal oxygen aging being the main failure mechanism. Without adding heat resistant, PA66's strength drops to 50% at 120°C for 2000 hours.
Must be combined with antioxidant + heat stabilizer as a dual-piece set, maintaining 80% at 5000 hours. This is the primary criterion for selecting materials for home appliance components.
Deeper Layer: Thermal-Oxygen Aging—The Slow Knife in Closed Systems
Talking About Compressor Components, The concept of thermal-oxygen aging is worth elaborating on separately, because almost all failures in closed systems are dominated by it.
Mechanism of thermal-oxygen aging: Oxygen (even residual oxygen in sealed systems) attacks polymer chains under temperature catalysis, chain breakage and crosslinking occur simultaneously—materials become brittle, harden, and small molecules precipitate. This process is slow but monotonous: for every 10°C increase in temperature, the rate doubles. For parts with a ten-year lifespan, accelerated tests are calculated according to this pattern.
There are three amplifiers for thermal-oxygen aging in compressors: refrigeration oil (oil extracts and expands certain plastics, accelerating aging), winding heat (terminal block close to winding, local temperature 20-30°C higher than the nominal ambient temperature), and refrigerant (Freon-based refrigerants can plasticize some plastics; R600a system compatibility requirements differ from R134a).
Material side response is prioritized: use thermal oxygen aging resistance plates (RTI 140 level oil-compatible system) for terminal blocks and windings close together; for structural parts far from heat sources, use general oil-resistant brands; Verify composite aging with "thermal oxygen oil immersion"; validating under single conditions will overestimate lifespan.
Another engineering reminder: failure of sealed system components has no warning — unlike outdoor parts that have "distress signals" like chalking or discoloration, failure of plastic parts inside the compressor directly indicates overall machine abnormalities. Therefore, material verification of sealed systems should be conducted according to the "worst-case scenario full test," trading thousands of laboratory hours for ten years of on-site silence.
Dimensional Stability and Dynamic Balance
High precision is required for motor rotor dynamic balance; dimensional stability of the end cover bearing chamber directly affects noise and lifespan.
PA66 Moisture absorption increases; the bearing housing size should have a moisture absorption margin or PBT.
Additionally, the fit between the end cover and stator must be interference or transitional fits, with dimensional tolerances ±0.05 mm, requiring high injection molding precision.
The pressure of energy efficiency ratings
Home appliance energy efficiency standards are constantly being upgraded, and every 1% improvement in motor efficiency requires tremendous effort.
This means reducing friction losses, vibration, and temperature rise for plastic parts.
Specifically, it involves high-dimensional precision bearing housings, low-friction fan blades, and excellent heat dissipation design.
Materials play a supporting role in this chain, but if the supporting role is not done well, it will drag down the main character.
Engineering Testing: 4 mandatory tests
Test 1: Thermal-oxygen aging at 120°C for 2000 hours. With the added antioxidant dual-piece PA66 set, the strength remains at 80%; without it, it drops to 50%—the motor parts must be added.
Test 2: Refrigerant resistance. PPS is stable at R134a + 120°C refrigerant oil, ordinary PA66 swells—compressor internal components use PPS.
Test 3: Dimensional stability. PBT moisture absorption changes by 0.1%, PA66 up to 0.35%—bearing housing prefers PBT.
Test 4: Flame-retardant CTI. PBT-GF25 halogen-free flame-retardant V-0 + CTI 500 V — standard configuration for the frame.
Follow-up questions: The three most frequently asked questions in procurement
Question 1: How to separate the end cap and frame. The end cover is attached to the winding heating zone, using the RTI 140 heat resistance rating; The frame (winding frame) directly contacts the enameled wire and impregnated varnish, so an additional test is required: "compatibility between enameled wire paint and impregnated varnish"—the solvents in the paint attack plastics most strongly during the curing residual period. The temperature and medium of the two positions differ; a single material is a long-standing pitfall in the compressor industry.
Question 2: Why are dimensional stability and dynamic balance important? At high compressor speeds (3000-6000 rpm), even slight deformation of internal plastic parts transmits vibration and noise: creep of rotor sheaths and balance brackets directly indicates excessive overall machine vibration. Verification of dynamic balance retesting after thermal aging—factory dynamic balance passing does not mean passing ten years later; aging and creep quietly take away balance.
Three questions: What does energy efficiency rating force into? The new energy efficiency regulations raise compressor efficiency lines year after year. The two contributing points of plastic parts are: lightweighting (rotor assembly weight reduction, inertia reduction, starting energy consumption) and low friction (oil-containing wear-resistant systems reduce mechanical losses). The material names are written in the energy efficiency files—many OEMs haven't realized this yet; the supply chain that realizes it first gets orders. ### Doing a Material Count: Inspection Premium for Closed Parts
The material ledger for closed system parts like compressors is structurally the opposite of open parts: material costs are very low, failure costs are high, and the inspection premium is the core account
For internal components like terminal blocks, the material cost per piece is less than 2 yuan, while specialized low-creep grades cost 0.5 yuan more. This 0.5 yuan price difference reduces the probability of 'bulk contact resistance drift after five years' from the level that has already occurred in the industry to nearly zero.
Failure cost: The compressor is not repaired individually; if it fails, the entire unit is scrapped. Based on the full after-sales cost of a refrigerator compressor unit (compressor, refrigerant, labor, on-site service) of 400 yuan, for every percentage point increase in the failure rate, the expected loss per 100 units of the model is 400 yuan—which is dozens of times the annual material price difference of the terminal seat.
More structural accounts on the brand side: The warranty period for refrigerators generally starts at ten years, and the failure rate of the compressor is directly linked to the financial model of the whole machine's warranty. Every upgrade in the material grade loosens the actuary model of the ten-year warranty.
The characteristics of the closed-component supply chain are also determined by this accounting: once finalized, the complete machine manufacturer does not change materials for ten years and does not easily change suppliers. For modifier factories, this is the longest tail in the long tail — the profit per piece is thin, but a fixed point can be earned for ten years. In the market competition of closed components, what is tested is not the quotation sheet, but the thickness of ten years of accelerated verification data. ### Boundary Statement
| Operating condition | Recommended materials |
|---|
| Motor end cover | PA66-GF25 Heat Resistant |
| Insulating framework | PBT-GF25 High CTI |
| Compressor components | PPS or refrigerant-resistant special material |
| Cooling fan | PA66-GF30 |
| High heat resistance required | PA66 Antioxidant Heat-Stable Two-Piece Set |
Engineering Memo
Before mass production of household appliance motor parts, three tests must be done: 120°C thermal-oxidative aging, refrigerant resistance, and dimensional stability. The dual-component anti-oxidation and thermal stability is standard; without it, it will become brittle in two years.
Practical Case Study: Common Pitfalls and Correct Solutions
Pitfall 1: Selecting materials for home appliance motor parts based on room temperature property tables without considering long-term operating temperatures. Home appliance parts operate long-term at 60-90°C, and even if room temperature strength is high, they will fail due to thermal aging. Correct approach: use data after thermal aging for material selection. For PA66 operating long-term at 80°C, choose a grade resistant to heat and oxidative aging.
Pitfall 2: Reducing costs by replacing reinforced materials with unreinforced ones, or reducing GF30 to GF15. The glass fiber content of home appliance motor parts is calculated, not arbitrarily decided. Correct approach: reducing glass fiber content requires recalculating creep and strength, and cannot be based on experience.
Pitfall 3: Investigating noise and abnormal sound issues only at the end, discovering they are caused by plastic parts friction or looseness. Correct approach: noise complaints make up a high proportion in home appliances, and the tolerance and self-lubricating properties of plastic parts must be determined during the design stage.
Reverse Case: Five-Year Accounting Period for Terminal Creep
Write down the entire timeline of the previous terminal block case, it is a standard example of failure in a closed system.
In 2020, the compressor was revised, and the terminal block was switched from the original supplier to a new supplier. The grade name remained the same, but the formulation system was different—the flame-retardant system of the new material was changed, and nobody rechecked the creep properties. Shipments that year were normal, and all factory tests were passed.
Since 2023, after-sales channels have gradually reported 'refrigerators not cooling.' The proportion is low but has been increasing year by year. Disassembly and inspection indicate: terminal blocks creeping, terminal clamping force weakening, contact resistance rising from milliohm level to ohm level, and abnormal start capacitor circuit.
Rectification completed in 2025: Terminal blocks are replaced with low-creep brands, contact resistance is retested after 5000 hours of thermal aging to meet standards, and the supplier system audit adds a "Key Parameter Change Reporting" clause.
The general ledger over the past five years: after-sales compensation, brand reputation, and dealer confidence have cumulatively resulted in seven-figure losses; the price difference of the terminal seats themselves is less than 100,000 per year.
The quality director of the compressor factory said during the review meeting: 'The failure of closed system components, the accounting period starts from five years ago—the purchasing decision made five years ago is paid for by after-sales five years later.' This sentence was later printed on the backdrop of their supplier conference.
For material changes in a closed system, the strictness of the review should be determined according to 'whole machine scrapping,' not based on 'single item cost.'
Extended judgment: Do not reverse the verification order
The verification of home appliance motor parts follows a fixed sequence; skipping the earlier steps and directly doing the later ones is equivalent to doing it in vain.
Step one is to verify the material itself: mechanical, thermal, flame retardant, and electrical properties, to confirm that the part number was not selected incorrectly.
Step 2: Verify the process window: For the same batch of material, parts produced under different mold temperatures and different holding pressures may show performance differences of over 20%, so the process window needs to be determined.
The third step is to perform validation on the complete machine or complete part: install it in actual working conditions to test its lifespan. Many people do it in the opposite order—they directly install the machine to test its lifespan, and if it fails, they don't know whether it's a material problem or a process problem, so they keep changing materials repeatedly and can't get results for half a year.
Write these three things into a table and send it to the supplier; it’s more useful than making ten phone calls—the communication cost for selecting household appliance motor parts is mostly spent on repeatedly confirming these few items.
Supplementary Note: Three On-Site Judgment Signals
Signal 1: The overall machine vibration and noise gradually increase. Internal plastic parts creep or wear; disassemble and inspect the rotor and bracket position, and recheck the dynamic balance according to the aged condition.
Signal 2: Startup abnormality, capacitor circuit voltage loss. Terminal block contact resistance drift, check the entire batch according to batch number, verify the terminal block material file; this is a safety-level signal.
Signal three: Abnormal color change when adding refrigerant to the circuit. Contamination of the system by plastic components' deposits; switching to low-deposit brands is a permanent solution, filtering only provides temporary relief. ### Verification sequence: Complete three steps before placing an order.
Step one, compound verification: thermal-oxidative aging, oil immersion, and refrigerant compatibility; the verification of a closed system is always under compound conditions.
Step two, verify for ten years: Creep and contact resistance are taken according to accelerated conditions converted for ten years; passing factory inspection does not mean passing for ten years.
Step three, lock changes: changes to key parameters (flame retardant system, filling system) must be mandatorily reported. The formulation stability of the closure parts is the lifeline of the product. Only after completing these three steps does the exemption-from-inspection commitment for the closure system have material support.
Conclusion
After sending out the sample—when it comes to material selection, the earlier you ask, the easier it is.
The material selection and mold trial for this type of part can be discussed together.
