Eplamid 66 GFS 35 HS BK Q2D506

Laboratory conditions are 23 ±2°C and 45-55 % RH.

Polyamide 66 is easy to mould material, which is not particularly sensitive to moulding conditions.
A few general guidelines are given here.

Polyamide is hygroscopic and moisture sensitive, so pre-drying is recommended as a matter of rule. Material that is not pre-dried to a moisture level below 0.1 % will degrade, causing surface defects, parts that are out of dimension and brittle parts. It is recommended to dry material for 4 hours at 80°C to 85°C in a desiccant dryer with more than one desiccant element.

A few tips to ensure proper operation of the dryer:

• Ensure the thermocouple that regulates the temperature is placed immediately before the entry of the air into the dryer. There can be a significant temperature drop in the air-conveyance system.
• The temperature of the air going out of the dryer silo should not be more than 30°C lower than the air entering the system. If this is the case, you have insufficient air capacity.
• From time to time, monitor the dew point of the dry air to ensure the desiccant elements are functioning properly.
• Often, less air runs through the very bottom part of a dryer silo. Therefore, it is recommended that you take the material out of the bottom of the dryer and feed back into the top when you start up your process. 

For polyamide 66, the melt temperature must be kept below 300°C. Any higher temperature will cause rapid degradation, which can be recognized by foaming of the material or splash marks on the surface of the part.

The following barrel settings are recommended:

 Tool temperature

Mould temperature is always a compromise. Moreover, tool temperature should be as a high as possible to give optimum crystallization, dimensional, good surface finish and excellent mechanical performance. On the other hand, lower tool temperature can significantly cut cycle time. For Polyamide 66, 80°C should be maintained as a minimum. For reinforced grades values of 90-110°C are preferred.

Pressure and speed

Injection pressure should generally be around 70 to 120 Mpa; this results in a minimum clamping force of the moulding machine in tonnes of 0,7 times the projected surface area in cm²

Holding pressure is generally in the area of 90 Mpa.

For glassfibre reinforced compounds, the screw speed should be kept low, a rough indication is as follows:

Back pressure should be kept to a practical minimum. 

Regrind sprues and runners can be used on most materials. It is not recommended to use regrind on FR grades. When regrind is used, observe these simple rules:

• Use a constant ratio of regrind and virgin material. When a material has been processed once, its viscosity and fibre length have been decreased. Using varying rations of regrind can lead to variations in dimensions, mechanical performance and processing characteristics.
• Either feed the regrind straight back into the machine or pre-dry the regrind before usage.
• Store regrind in a dry, clean place to avoid contamination and excess moisture.
• Ensure sharp cutting blades to keep dust generation to a minimum; cut glass fibre reinforced material when it is still hot.
• Clean the grinder regularly to avoid build up of dust.
• Do not use splayed, discoloured or degraded parts and runners.