Mechanical Processing Guide | Kestamit | PA6G

Drilling Process

Drilling is the most difficult of mechanical machining processes due to the fact that the drilling takes place in a confined space and the poor heat conduction of the cast polyamide. The use of appropriate equipment and attention will prevent problems such as breakage, cracking and surface deterioration. The slow drilling operation will enable the chip to be ejected faster and more efficiently by using large grooved drill bits. For best results, use a new drill bit and grind the drill bit to reduce the resistance surface, providing a positive inclination angle of 0 to 5 degrees at the cutting edge. For small drill bits, an angle of 90-110 degrees is ideal. For larger drill bits, an angle of 118-120 degrees is recommended. Standard drills used for metals should never be used for casting polyamide drilling. Frequent use of coolants is essential for successful drilling. When the maximum half of the desired depth is reached during the drilling process, the drill bit must be completely removed and the sawdust accumulated in the channels must be ejected. For drilling, it is very important to first drill a small guide hole (maximum Ø8mm) and then expand the hole to the desired size. Otherwise, the product is likely to experience cracking and breakage due to chip jamming and surface tension in a narrow space. It is recommended to comply with the requirements of the turning process during finalizing the bore.

Milling Process

Air steel cutter inserts designed for non-ferrous metals are generally recommended. For better performance, the boring bar can be used but is considerably slower due to the chip removal rate. The blades must be sharp and have a high positive cutting and inclination angle. The part must be fully supported during all operations on the mill. When clamping or holding is required, it is important to use intermediate equipment to prevent deformation of the part.

Annealing Process

Annealing process is applied in order to reduce the internal tension that may occur as a result of the production process of cast polyamide products. The annealing process is extremely important to ensure dimensional stability of the parts. Intermediate annealing is required in some mechanical machining processes. For example, it is important that parts subjected to intensive mechanical treatment from one side to the intermediate annealing process. During the annealing process, the product should be heated to 65 ° C / 10 minutes. The annealing temperature should be between 137 ° C and 150 ° C for 30 minutes for each 6.35mm profile thickness. The cooling process should not be carried out in a sudden and shocking manner and the cooling speed should not exceed 150 ° C / hour.

Turning Process

Cast polyamide products must be turned under the same conditions as free-cut products. The lathe speed should be adjusted considering the possibility of expansion and deflection of the material during chip removal. Processing should be carried out at 600 to 1000 rpm. When turning parts with large diameters and surfaces, firstly rough machining should be done and sawdust should be removed. It is recommended to allow the part to rest for 24 hours and allow to cool before final passing and final dimensioning. Only in this way will the desired net measurements be achieved. It is recommended to use air steel equipment with suitable slope and opening to reduce resistance during machining. It is generally sufficient to use air steel equipment for high speed turning. However, it is recommended to use carbide-tipped tools for long-term turning.

Sawing and Cutting

All cast polyamide products can be cut using standard woodworking, metalworking bands or circular saws. Both blades must have wide spaced teeth with offset (left, right and center) and a deep gum. This ensures that the blade of the blade is farther away from the saw body and provides a place for the sawdust to sit as it passes through the material. The discharge of the sawdust immediately after the saw has exited the material will help prevent the blade from jamming in the material due to heat build-up. Generally, this problem can be avoided by using air or cooling water.

Threading Process

Threading of cast polyamide products can be done by hand or machine. It is recommended that the equipment used on metal should not be used on cast polyamide parts.

Legal warning

The information and recommendations mentioned above are based on experiments believed to be reliable and our experience as Mega Polimer. However, there is no guarantee of accuracy. Purchasers are required to carry out the necessary tests to determine their suitability for their intended use. Our company cannot be held responsible for any damages that may arise under any circumstances.