Shanghai Daoqin Plastics Co., Ltd.

一, nylon classification and features
　　 classification:
　　　　1, according to binary amine and binary acid carbon 原子数, types mono combined formed nylon has:
  　　　46, 66, 610, 612, 613, 1010, 1313
 　　　 2, according to mono 体 含 carbon 原子数命名 has:
  　　　 nylon 4, 5, 6, 7, 8, 9, 11, 12, 13
　　 features
　　　　 nylon has excellent tough property, lubricated property, wear resistance, chemical resistance, gas property, and oil resistant property, and easy color and other advantages, therefore 尼　　龙 in industrial upper to application.
二, nylon process features
　　
　　 nylon features: nylon large more is crystallization property resin, temperature degree ultra- its melting point rear, its melt viscosity relatively small, melt flow property good, anti 止溢边 发生. meanwhile due to solvent cold speed degree fast, anti material material retardant nozzle, runner, gate and other products phenomenon. mold value 0.03, but also melt viscosity for temperature degree and force 变化都 comparison 敏感, for temperature degree more add 敏感, reduce melt viscosity from material temperature degree 入手.
　　 nylon water and drying: nylon water property relatively large, wet nylon in molding process in, performance is viscosity decline mixed has bubbles products surface silver streaks, products machine strong/high degree decline, therefore processing front material drying.
　　部 separation nylon injection water separation content:
   resin 名称          nylon 6, 66       nylon 11     nylon 6 10
   允许含 water amount %         0.1               0.15           0.1-0.15
 
   nylon PA66 drying
                              true drying               hot drying
    temperature degree ℃                 95-105                   90-100
    time h                   6-8                        4 left right

　　 crystallization property: 
        remove transparent nylon outer, nylon large is crystallization high poly material, crystallization degree high, products tensile strength, wear resistance, hardness, lubricated property and other property can has improve/increase, 　　 thermal expansion coefficient and water property decline, for transparent degree and impact resistant property can has 不利. mold temperature degree for crystallization effect/influence relatively large, mold temperature high crystallization degree high 　　, mold temperature crystallization degree 底.
　　 shrinkage rate:
     　 and other crystallization plastics versus 似, nylon resin in shrinkage rate relatively large issues, generally nylon shrinkage crystallization most large,当 products crystallization degree large made 　　 product shrinkage add large, in molding process in reduce mold temperature degree add large injection pressure reduce material temperature decrease small shrinkage,但 products internal stress add large easy deformation 　　.PA66 shrinkage rate 1.5-2%
    molding equipment
   　　　 nylon molding 时, main/primary attention/notes anti 止“ nozzle phenomenon ”, therefore for nylon material processing generally selection 自锁式 nozzle.
    products and mold
      1, products thick   nylon long ratio is 150-200 between, nylon products thick 不底于0.8mm generally in 1-3.2mm between selection, but also 　　 products shrinkage and products thick has 关, thick thick shrinkage large.
　　　2, gas nylon resin value is 0.03mm left right, therefore gas 孔槽应 control in 0.025 below/following.
　　　3, mold temperature degree products thin difficult molding or requirements crystallization degree high mold add temperature control, requirements products has flexibility property generally using/adopting cold water temperature.
三, nylon molding process
　　 material temperature degree    nylon is crystallization type polymer, therefore melting point obvious, nylon type resin in injection molding selection material temperature degree resin property can, equipment, products factors has 关. generally nylon 6 solvent temperature degree most low is 225℃, nylon 66 is 260℃. * due to nylon heat stabilized property relatively 差, therefore high temperature long time in material in 停留, 以免引起 material material color 发黄, meanwhile due to nylon flow property relatively good, temperature degree ultra- its melting point rear flow speed.
injection pressure    nylon solvent viscosity low, flow property good, is cold speed degree relatively fast, in complex and thick relatively thin products upper easy 出现不足 issues, also is need relatively high injection pressure. usually pressure high, products 会出现溢边 issues; pressure low, products generate 波纹, bubbles, obvious 熔结痕 or products and other defect, large more nylon product types injection pressure ultra- 120MPA, generally in 60-100MPA scope/range inner is meet/satisfy large separation products requirements, need products 不出现 bubbles, and other defect, generally 不希望 using/adopting relatively high holding pressure pressure, 以免造 formed products internal stress increase.

　　　 injection speed degree    for nylon 而言, injection molding speed degree fast is 益, can anti cooling speed degree fast formed 波纹, 充模不足 issues. fast injection speed degree for products property can effect/influence 并不突出.
　　　 mold temperature degree    mold temperature degree for crystallization degree and molding shrinkage has effect/influence, high mold temperature crystallization degree high, wear resistance, hardness, elastic property modulus increase, water property decline, products molding shrinkage increase; low mold temperature crystallization degree low, tough property good, elongation relatively high.
四, nylon molding process parameters table/sheet
  project                             nylon 66                     glass fiber reinforced nylon 66
material temperature degree ℃ rear 部            240-285                    290-300
                in 部            260-300                    285-320
                front 部            260-300                    285-320
nozzle temperature degree ℃                   260-280                   280-285
mold temperature degree ℃                   20- 90                     80-85
injection molding pressure MPA                 60-200                    60-200
screw speed R/MIN              50-120                    50-120      

五, molding nylon precautions
1, recycled material use most good ultra- 三次, 以免引起 products color or machine physical properties decline, application amount control in 25% below/following, more 会引起 process conditions 波动, recycled material and new material mixed combined must drying.
2, safety must 知   nylon type resin machine 时应首先开启 nozzle temperature degree, rear in to material add temperature, nozzle retardant 塞时, 切忌面 for 喷孔, anti material inner solvent pressure poly 集而突然释放, 发生危险.
3, demolding agent use   use a small amount of demolding agent has for bubbles and other defect has improvement and remove function. nylon products demolding agent can selection hard acid zinc and and other, can mixed combined formed use, use must amount less uniform, 以免造 formed products surface defects.
4, in machine need screw, anti lower production 时,扭断 screw.
六, nylon products rear 处理
products rear 处理:   nylon products rear is is anti and remove products in 残留应 force or wet function dimensions 变化. rear methods has hot method and wet method types. 1. hot 处理  commonly used methods in material 油, 甘油, liquid wax and other high liquid in, hot temperature degree high use temperature degree 10-20℃, time products thick 而异, thick degree in 3mm below/following is 10-15 separation 钟, thick degree is 3-6mm time is 15-30 separation 钟, hot products attention/notes slow cooling room temperature, anti cold products in force heavy new formed. 2.调 wet 处理  wet main/primary is for use ring wet degree relatively large products 而进行, its method has types: water wet method, acid water solvent liquid wet method （醋 acid and water ratio/proportion is 1.25:1,沸点121℃）,沸 water wet method 简便, need will products in wet degree is 65% ring lower, make its to balanced wet amount can,但 time relatively long,而醋 acid water solvent liquid wet method temperature degree is 80-100醋 acid water solvent liquid wet method,处理 time main/primary products thick,当壁 thick is 1.5mm时约2 small 时,3mm is 8 small 时,6mm is 16-18 small 时.
七, nylon products Common defect and 处理
　　注- injection molding pressure unstable
           generally this type of 情况同 injection molding machine 射咀孔 small has 关, is is mold long 期接触, mold temperature degree very low 20-90 ℃, temperature degree 240-280 ℃, between in temperature difficult 免会发生 hot 交换, 当射咀 temperature degree drop to nylon melting point below/following 时, 射咀孔 by 冻结, in lower injection large pressure 冲开, formed pressure loss generate *注, this add large injection molding pressure rear, production rear also 会涨模. from phenomenon is injection molding machine injection molding unstable, its is 射咀孔 small, add large 射咀孔 this phenomenon 就会消失.
    PA POM ABS this types material generate this type of issues
波浪形 flow marks
   generate mechanism is material in mold cavity inner speed slow, rear material has method mold.
solution methods:
    1, improve/increase injection speed degree
    2, improve/increase mold temperature degree
    3, improve/increase material temperature degree
    4, increase 射咀孔径 or gate
silver streaks
     generate mechanism is good material in has gas 体, in injection gas in mold surface by strong/high pressure 出, in products surface white filament 纹.
solution methods:
     1, is raw materials wet or mixed other raw materials
     2, raw materials is in material in separation understanding （ material temperature
          degree high, screw speed fast ）
     3, 检查射咀孔 is small
     4, is mold temperature low
     5, mold gas defect
     6, gate dimensions is small
     7, back pressure low, recycled material application more
        
熔接痕
   generate mechanism is in flow 末端胶 material temperature degree very low combined property relatively pressure low, this make material combined 不紧密.
solution methods:
    1, improve/increase injection pressure, speed degree
    2, improve/increase mold temperature
    3, improve/increase material temperature
    4, improvement mold
         gas
shrink 孔
   generate mechanism is products *注 or sink marks.
if is *注 use *注 methods solution
if is sink marks use sink marks methods solution    
焦斑
  generate mechanism is injection material high speed mold cavity mold cavity inner gas 体 不 and troubleshooting 时, this separation gas by pressure shrink, gas pressure shrink rear rise temperature products 烧焦
solution methods:
      1, reduce injection molding speed degree or pressure
      2, reduce melt temperature degree
      3, improvement mold gas
      4, decrease small clamping force
      5, increase large 射咀孔径
demolding defect
1, mold temperature control 不当, make shrinkage 不均造 formed force 不均.
2, products inner injection residual stress large, make its generate large force make demolding difficult.
solution issues methods:
       1, reduce injection, holding pressure pressure;
       2, reduce injection, holding pressure time
       3, improve/increase or reduce material temperature.
       4, improve/increase or reduce mold temperature.
       5, mold 拔模斜 degree
warpage deformation
  generate mechanism is products internal stress large, products shrinkage 不均.
products internal stress large:
       1, reduce injection pressure, reduce injection time, reduce holding pressure pressure, reduce holding pressure time
       2, improve/increase material temperature, improve/increase mold temperature degree.
products shrinkage 不均:
       1, reduce material temperature, reduce mold temperature degree, improve/increase cooling time.
       2, improve/increase injection pressure, improve/increase injection time, improve/increase holding pressure pressure, improve/increase holding pressure time.
other causes: 1, gate setting combined 理
                2, products thick 设置不 combined 理
                3, mold structure 设置不 combined 理
nozzle 流涎
  this issues is in production nylon 经常遇 to issues.
main/primary solution methods:
     1, add large rear 抽胶.
     2, reduce material temperature, reduce nozzle temperature degree.
     3, raw materials drying separation.
     4, add elastic 弓射咀
塑化 defect
    1, back pressure low
    2, material temperature degree low
    3, screw speed fast
    4, molding cycle short