During the process of embedding metallographic samples, the problem of sample cracking is believed to have been encountered by most people. How can we solve it? Our method is to use a METPRESS A hot press inlay machine with QMAXIS metallographic inlay material, combined with some divine operations, and that's it!


Let's understand the causes and specific solutions of cracking defects in embedded samples. Common cracking defects include central cracking, circumferential cracking, and expansion cracking. Let's explain one by one below.

1. Center cracking: When the embedded sample size is too large and there are sharp edges, it is easy to produce center cracking. Because such a large-sized sample with sharp corners is placed in the shaping cavity, the space inside the shaping cavity will be relatively narrow and limited. The sharp corners are located close to the edge and cannot be filled with sufficient thickness of inlay material. As a result, cracks will appear during shaping, resulting in a central cracking situation.


In response to this situation, appropriate measures should be taken to reduce the size of the sample in order to facilitate a more sufficient space for filling the molding cavity with embedded materials; Colleagues should choose inlay materials with hardness that match the sample material, so as to avoid defects such as center cracking. However, if the technical requirements for the size of the embedded sample cannot be reduced, it is necessary to reconfigure a large-sized shaping cavity to solve the problem.




2. Circumferential cracking is likely caused by the inclusion of moist air in the inlay material, or by the inclusion of air during the inlay shaping process.


In response to this situation, after starting the metallographic inlay machine, preheat the inlay powder or pre form the inlay powder before inlaying the sample. The entire inlay process is monitored in real-time, and when the inlay material is in liquid form, the pressure is instantly released. By doing so, the problem of circumferential cracking can be effectively avoided.




3. The occurrence of expansion cracks is caused by the short curing time set during the embedding process or insufficient pressure.


In response to this situation, we need to choose a reasonable hot embedding resin, extend the curing time appropriately, and increase the pressure appropriately from the liquid state of the embedding material to the curing molding period. This operation can effectively avoid expansion and cracking defects.

The above operations are a summary of the experience of pulse detection engineers and are shared with everyone. The metallographic inlay machine used is the METPRESS A single cylinder fully automatic hot pressing metallographic inlay machine, equipped with consumables of QMAXIS hot inlay powder. The relevant technical parameters, performance, and application of this metallographic inlay machine and inlay material will not be elaborated here. The above mentioned methods are hoped to be helpful for your similar problems. If you encounter any issues related to metallographic sample preparation, you are welcome to contact the application engineer of pulse detection, and we are willing to explore solutions together with you.