How to Inspect a Used Injection Molding Machine Before Purchase

If you buy used injection molding machines for sale, an attentive inspection could reduce the cost of repairs and time. This guide will assist you in evaluating the condition of an import or used imported injection moulding machine before paying. It is simple and straightforward for buyers from the United States.

Beginning with the history of the machine

Before even looking at the machine, you should ask to know the basic facts. Ask for the manufacturer, model and the year it was built and the number of hours it has run. You should inquire about the number of owners the machine has had as well as what kinds of materials the machine used. An accurate history can help to determine the quality of the used injection molding machines.

It is also recommended to ask for service records and repair logs. Check for any notes on large overhauls, hydraulic reconstructions and electrical upgrade. If the seller does not have documentation or conceals their history consider it an indication of danger. The absence of records usually indicates inadequate maintenance of an imported injection moulding machine.

Perform a thorough visual inspection

Go around the entire machine, and inspect it from all angles. Check for oil leaks from the floor, spots on the bottom, or even rust in the frames. Look for cracked, dented panels, or loose bolts. The clean machines typically indicate the best care. However, unclean or messy machines often indicate disregard.

Be particularly attentive to the safety components. Check that all covers, guards and emergency-stop buttons are properly installed and have not been damaged. If any safety component is not present or damaged buyers may have be replaced prior to the use of the equipment. This increases the cost of production and may delay the commencement of production.

Inspect the clamping unit

The clamping unit is used to hold the mold, and it applies the pressure throughout each cycle. Close and open the mold with a gentle pressure then observe the way it moves. The motion should be smooth and quiet, not with noise or grinding. If you notice unusual noises then the tie bar or the hydraulic system could have worn out.

If it is possible, determine the degree of parallelism between the plates. Incorrectly aligned plates can harm molds and result in irregular components. Verify the tension on the tie-bars and face of the platen to check for scoring or cracks. This can be very costly to repair on used injection molding machines.

Check the injection unit

After that, take a look at the barrel and screw inside the unit of injection. Take off the barrel cover and look at the screw’s area. The surface should be wearing evenly but not a lot of damage or loss of the metal. Abrasions that are severe can decrease the quality of melts and make it difficult to keep tight tolerances. Inject the stroke into the cylinder then monitor the speed and pressure. Each shot should be the same, and there should be no abrupt drops or surges. Request the vendor to make a quick shot using the use of a basic mold. It will let you know the way in which the machine measures and moves material.

Evaluate hydraulic and electrical systems

Verify the oil level in the hydraulic tank and the color of the tank. A light, clear-colored and clean fluid is best. The presence of oil that is dark or gritty suggests that maintenance is overdue. Find leaks in the valves, hoses, or the pump. Every leak can cause downtime as well as additional oil expenses.

The electrical cabinet should be opened and check for loose wires burning parts or significant dust. The presence of dust and faulty wiring could result in overheating or control issues. Check the screen for control and alarm system as the machine is running. The alarms should be easy to read and easily reset.

Run a production trial

Make sure you see the imported injection moulding machine actually running under thepower of. Request a quick manufacturing cycle using a basic mould. Be aware of the cycle’s time as well as the pressure curves and the part’s consistency. If the device changes its cycles or changes in pressure between shots, it could need to be repaired.

During the testing, watch out for unusual sounds and/or vibration. See how the machine responds to inputs from the operator and changes to the recipe. An efficient machine will run the same routine without much variations. If it is acting differently each cycle, it’s probably not worth the investment.

Match the machine to your needs

Be sure that the specs of the machine match the parts you are planning to use. Take note of theclamping force, the weight of the injection, as well as the diameter of the screw. Check these against the components you’d like to mould. Make sure the nozzle size and tie-bar spacing is compatible with the molds you are using.

Check that the machine is able to handle your type of resin and changes in color. Certain machines are designed exclusively for certain resins. If you are using different resins make sure that the barrel and screw can be used together. Inadequately addressing this issue could result in low-quality or weak parts.

Review safety, controls, and documents

Verify that the safety features function effectively. Check each emergency stop button as well as the security interlock by talking to the person who operates it. Verify that the alarm system is simple to comprehend. Security issues need to be addressed before production can begin.

Get the original manuals as well as wiring diagrams and lists of spare-parts. The documents you have will assist you to solve problems and keep the machine running. In the case of imported injection moulding machine documents that are accurate and complete is essential.

Consider logistics and costs

Consider transportation, unloading, and the installation process before you decide on the price. The large used injection molding machines that are used in the past require cranes, rigging and the floor to be solid. Make sure that the plant is equipped with sufficient energy and compressed air to run the machinery.

Determine how much it would be to replace worn components. Some machines are less costly and require higher repairs than a higher priced one. A thorough inspection could aid you in selecting the ideal quality, and not just the lowest cost.

By following these steps, you greatly reduce the risk when buying used injection moldingmachines or an imported injection moulding machine. A few hours of careful checks today can save months of downtime and lost profit tomorrow.