Why conditioning?
Conditioning means adapting materials to the necessary conditions before further processing.
This process is particularly important regarding engineering polyamides. The dry and brittle material obtains its desired characteristics only through water absorption. While impact resistance and stiffness decrease under the influence of humidity, ultimate strain increases. This must be considered already upon design phase. On the part drawings the required absorption of humidity shall always be specified in %.
It is very important to condition polyamide plastics regardless of weather conditions.
- Polyamides show a particularly high affinity of absorbing water; this process is also enforced through natural humidity, but takes almost a year with the absorption of water stagnating at frost.
- The dimensional stability of the components is kept.
- After the absorption of water, polyamide parts undergo a fundamental but positive change of characteristics, which is very important to the usability of components, e.g. upon installation.
- Only conditioned components meet the quality requirements.
- Avoidance of wastrels, complaints and failure of the assembly plants.
- With this process you will achieve a high quality of your products and thus a large customer satisfaction.
Most widely used methods
The water basin
A very common method is the use of a water basin, into which the parts are plunged in a basket. The water is usually heated up to 60 to 80 °C.
Disadvantages:
– High energy consumption
– Spotting
– Uncontrolled dwelling time and thus consistent quality cannot be guaranteed
– High handling costs
– Items must be dried
The „steam cabinet“
This method usually employs unpressurised steam.
Disadvantages:
– High energy consumption
– High personnel expenses
– Long dwelling time
– Spotting
The „climatic chamber“
The “climatic chamber” is the walk-in version of the steam cabinet, in which the parts are stored in a humid atmosphere of up to 90% relative humidity. These systems are often also accessible to forklifts.
Disadvantages:
– High energy consumption
– More floor space requirements
– High personnel expenses
– Very long dwelling time
All methods require huge efforts of control to guarantee quality. IMA Buscher GmbH applies – among others – a method which enables an automation of the conditioning process.
Advantages of the process:
Conditioning times are drastically reduced.
Some examples from practice:
– Case parts may be processed within one hour instead of 28 hours in the steam cabinet, or only 15 minutes instead of 16 hours in the water quench at 60 °C
– Fastening material: 20 minutes instead of 24 hours within water quench or 5 days in the climate cabinet
– Filler caps 20 minutes instead of 6 hours in the climatic chamber at 65 °C
Energy consumption: low, since only the space needed for the items is vaporised. In addition, the inline machine JK 6/14 has a low water consumption.
Parts handling: The expense is considerably reduced as the newly produced parts are immediately conveyed to conditioning. Transhipping is no longer required in inline operation.
Stock keeping: You may go without storage, since the parts leave the plant ready for shipment and installation.
Fire-retardant plastics: Washing out of phosphates is extremely low in this way of processing, which has been testified by a leading pellets producer. Tests at granulate producers´ have clearly demonstrated that there is not any structural change within the component taking place. Statement: “No damage to the product could be found”.
Quick conditioning without drawbacks