1: The correct connection, coordination and maintenance are as shown in (Figure: 1): (1) the injection plug rod, injection rod assembly and molten cup hole shall be coaxial and the axis shall be repeated. The connection shall be firm without obvious looseness. There shall be no obvious gap at the cladding.
(2) : the cushion block shall be replaced frequently (prepared according to the actual size between the injection rod and the piston rod).
(3) : the connection between the ejector rod, transition joint and ejector head shall be kept tight.
(4) : keep the cooling water unblocked.
(5) : the injection head shall be well lubricated. Special precautions:
(1) : do not use a bent ejector rod.
(2) : do not use the injection head with different inner hole thread and outer circle core, and the melting cup with different inner and outer circle core.
2: Incorrect connection and fit are shown in (Figure: 3)
Cause of the problem: due to thousands of injection shocks every day, the length of the cushion block between the injection rod and the piston rod is gradually shortened, resulting in the gap between the injection rod, the piston rod and the inclusion part of the split wrap clamp. When the gap is large to a certain amount, the results shown in (Figure: 3) will appear.
This is a problem that many factories have neglected for a long time. It causes permanent deformation of the end face of the injection piston rod (the end face is not perpendicular to the axis) or even fracture. Make the injection head, injection rod assembly and molten cup operate under the condition that different axes and axes do not repeat. Main features of fault:
(1). The ejector rod is often bent and deformed.
(2). Excessive joints often break.
(3). Always jam the ejector head. The service life of the ejector head is short.
(4). The single side wear of the injection head, the melting cup and the gate sleeve on the die is very fast. Aluminum liquid often splashes outward from the gap between the molten cup and the injection head. Or the flash on one side of the material handle is very large.
(5). The repeated precision of equipment injection action is poor, so that the product quality is unstable. Once this problem is formed, the ejector head will often be replaced in the production process, and the general technicians will give the wrong conclusion of "poor quality of ejector head and no wear resistance".3: The simple judgment method of brass alloy die casting machine is shown in (Figure: 4)
(1) Simple measurement: carry out physical die casting machine with manual program. After the die casting action is completed, measure whether there is obvious difference between the surrounding gap between the injection rod and the molten cup. If there is a large difference, it indicates that the injection rod or piston rod has been deformed (generally, it is normal if the center deviation is within 0.2mm). (2) After physical die casting, use manual program to repeatedly switch between injection and middle position to see the action status of the connecting part of injection rod and injection piston rod:
(a). If the injection rod and piston rod only make a small range of left-right linear movement, it indicates that the injection rod assembly is normal.
(b). If the injection rod, piston rod and connecting part have obvious up and down runout, it indicates that the injection rod or injection piston rod has been deformed.
4: Repair points for aluminium alloy die casting machine
(1). First, confirm whether the injection piston rod is bent or deformed at the end. If so, repair or replace it. The accuracy between the piston rod and the molten cup hole shall be tested during assembly.
(2). Confirm whether the dimensions of each part of the split clamp are normal. Replace if there is any problem.
(3). Replace the ejector rod assembly with a new one.
(4). Match the length of cushion block (usually the gap is within 0.1mm) and confirm that the split wrap clamp can clamp the connected parts.
5: Daily spot check
During normal production, the spot inspection shall be conducted every 24 hours.
(1). Check whether the screws of the split clamp are loose.
(2). Whether the ejector rod has obvious axial or radial clearance.
(3). Whether the connection between the injection head, transition joint and injection rod is loose.
6: Examples of multiple connection modes
Toshiba as a representative of conventional electrical appliances (the injection part has a travel switch) die casting machine usually collides with the travel switch in this way. This method has the advantages of simple structure, convenient, intuitive and reliable adjustment of travel switch.
At present, most domestic die casting machines adopt this structure (horseshoe floating connection). This connection method has many problems in use, so daily maintenance is more important.
