This video shows KRMOLD staff conducting a water connection test on a plastic injection mold and explains why this test is necessary. This is to ensure the cooling system meets design requirements after plastic injection mold assembly, preventing leaks, insufficient flow, and other issues after plastic injection mold use, thus ensuring plastic injection mold stability and product quality consistency. KRMOLD staff will check the plastic injection mold condition through three methods: visual inspection, pressure testing, and dye detection.
(I) Visual Inspection
Mold Surface: Carefully inspect the plastic injection mold surface for water stains, droplets, or water flow marks. Pay special attention to the cooling water inlets and outlets, water pipe connections, the plastic injection mold parting surface, and areas near the cooling water channels. These are common locations for leaks; even minor leaks may leave noticeable marks on the plastic injection mold surface.
Water Pipes and Connectors: Inspect the water pipes connecting to the cooling water system for damage, aging, or cracks. Long-term use of water pipes may be affected by pressure, temperature, and chemicals, leading to material degradation and damage. Also check for loose water pipe connectors and damaged seals. Loose joints or failed seals are common causes of water leakage.
(II) Pressure Test
Close Outlet: After ensuring the injection molding machine is stopped and the cooling system is in a safe condition, close the outlet of the cooling water circuit.
Inject Pressurized Water: Using specialized pressure testing equipment, inject water at a certain pressure into the cooling water circuit. Generally, the pressure can be set to approximately 1.5 times the normal operating pressure. During the injection process, observe the condition of the plastic injection mold and water pipes.
Check Pressure Changes: Maintain the pressure for a period of time, such as 10-15 minutes, and observe whether there is a significant pressure drop. If the pressure drops significantly, it indicates a leak in the cooling water circuit. At this point, the leak location can be further determined by listening to sounds and touching the area. A hissing sound may be heard from the leak, and water can be felt flowing out when touched.
(III) Dye Detection
Add Dye: Add an appropriate amount of dye, such as fluorescent dye or colored pigment, to the cooling water. The dye should be compatible with the materials of the cooling system and will not damage the cooling water circuit or the plastic injection mold.
Operating the cooling system: Start the cooling system and allow the water containing the dye to circulate in the cooling water circuit for a period of time to ensure that the dye is fully distributed throughout the entire cooling system.
Locating dyeing marks: After stopping the cooling system, carefully inspect the plastic injection mold surface and water pipe connections. Leaks will leave obvious dye marks due to dye seepage, making it easy to accurately locate the leak.
