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Mold use and maintenance manual

Views:1066     Author:Site Editor     Publish Time: 2021-04-14      Origin:Site

After the acceptance of the mold, in order to make the mold to maintain the best performance state and prolong the service life, to ensure the normal production and product quality, to reduce the production cost as far as possible, when the mold is used, please follow the following items for necessary maintenance and maintenance.

Mold production specification

First. Inspection and installation requirements before mold production

1、Before starting work, you must wear protective equipment, such as hard hat, work clothes and labor protection shoes. Wearing short-sleeved shirts, shorts and slippers is strictly prohibited.

2、Before the installation of the mold, first of all to confirm the die casting machine specifications and mold design requirements to match.

3、The die caster must have a thorough knowledge of the mold structure, including:

A、Check whether the mould has core pulling (dynamic mould core pulling, static mould core pulling, oblique rod core pulling and hydraulic core pulling).        

B、Whether it is necessary to install the pre-reset pull rod or strong spring of the ejector rod.

C、Check whether the combination size of sprue sleeve, flange and melting cup is consistent.

D、Confirm if it is the center sprue.

E、Check the top bar position for no interference and ejection balance.

4、Replace the molten cup punch according to the mold condition and adjust the injection lifting mechanism when necessary.

5、 Check the outer fastening bolt of the mold again, and confirm that there is no loosening phenomenon, the mold can be installed on the machine to ensure reliable installation of the mold.

6、Check the die casting machine and mold moving template and static template mounting surface: no foreign body, no high point.

7、Mould in die casting machine, to the right after tighten-up platen and installation is firm, and then to idle mode of the mould, check whether mold opening and closing smoothly and observe its each part movement is flexible, whether there are abnormal phenomenon, the ejection stroke, open schedule is in place, it fits the profile at the closing time, closely linking piece screws are tight, waterway, the oil was clear.

8、 Check the running of sliding parts on the mold. Such as guide post, guide sleeve, thimble, push rod ejection and other moving parts (bit) should be observed at any time, regular inspection, timely scrub and add lubricating grease, in order to ensure the normal and flexible operation of these sliding parts, to prevent tight biting dead. Adjust die closing, ejection pressure and distance, and install various auxiliary parts (such as water pipe, oil pipe, air extraction device). During the debugging process, check whether there is any damage, leakage or blockage in the connection of water pipe and oil pipe.

9、When the pressure plate bolts of the mold installation are firm and do not become loose, the mold will continue to open and close the die casting machine for three or four times for debugging. When the opening and closing are smooth and there is no abnormal situation, the test production of the mold can be started only after the workpiece is stable, reliable and flexible. In the production process, the guide part and the sliding part of the mold should be cleaned and lubricated frequently to ensure smooth, in place and free of stuck.

Second. The correct preheat production plan of the mold

1、If the die casting mold needs to be preheated before production, the cooling water of the mold shall be temporarily closed, and then the water volume shall be gradually adjusted according to the mold temperature. When preheating the mold, be careful not to make the mold local overheating (dark red phenomenon), in case the mold annealing.

2、When preheating the mold, it is forbidden to use two-block injection or pressurized injection.It must be heated effectively without damaging the mold according to the design requirements of the mold.For those with thermostatic tubing, use a mold temperature controller for heat preservation and heating.If there is no thermostatic tubing, gas can be used to increase the temperature. When heating, it should be done gently, evenly and slowly so that the temperature rise of the core and the core seat can be synchronized with the expansion.When the mold temperature preheats to about 220°, run each moving part to prevent the normal operation from being affected by the phenomenon of tight biting due to thermal expansion.After producing about 10 molds at low pressure, the high pressure production parameters were adjusted and qualified products were extracted.In the early stage of die casting production, it was found that the sprue part and the casting part of the finished product had the phenomenon of aluminum sticking pull caused by impact.If there is running material, should be cleaned up in time, otherwise the more tight the pressure, the more difficult to clean up.

Third. Cold mold production plan

1、The mold in the cold mold state, to brush more oil, less spray. When the mold temperature reaches the technical requirements after the normal spray coating. Then the two blocks and pressurized gradually open, and according to the normal process of production.

2、Mold in the case of no preheating to low-pressure production, and the production parameters on the machine must be reduced or closed to zero (remember: do not open fast injection to prevent mold run and stick).Every production of a mold to brush the oil or demoulding paste, to prevent the cold mold adhesion with material phenomenon (aluminum temperature had better reach 680℃ above, so the mold temperature rise faster).Low pressure production of about 30 molds, with the exhaust device and injection in each mold to close the exhaust valve in time, at the same time to observe the normal operation of the active parts, and then debug the production parameters of the machine until the production of qualified products and extraction of finished products.In the die casting production, it is found that the gate and the casting parts have the phenomenon of aluminum sticking pull caused by impact.If there is running material, should be cleaned up in time, otherwise the more tight the pressure, the more difficult to clean up.

Fourth. Matters needing attention in mold production

1、Before mold production, die caster should pay attention to the following requirements:

⑴In the cold mold state or in the shift, or the machine is not normal production and other circumstances, you must re-adjust the switch, and the two block and pressurized off. So as not to cross the machine or damage the mold.

⑵The handles, slag bags and wastes in the residual castings must be heated and dried on the furnace before adding the crucible to prevent spatter and injury.

⑶Before the machine is opened, it must be started by inching, and start the machine under the condition of ensuring no abnormality of the machine. No abnormal conditions include: normal temperature of hydraulic oil, lubricating oil, and open cooling water.

⑷It is strictly prohibited to adjust the opening of the machine tool, dismantle or move the safety protection components and devices of the machine tool in the clamping mold state.

⑸In the machine tool production process, must avoid the parting surface, in case of channeling aluminum, injury. 

⑹Power must be turned off when the machine is shut down, and the water inlet valve must be closed when the machine is shut down for a long time.

In winter, the water in the cooler must be drained to prevent the cooler from freezing.

2、Before casting production, the mold cavity, core, guide column, guide sleeve, ejector rod, reset rod, mold guide part and sliding part must be thoroughly brushed with oil.

3、If any abnormality is found in the casting production, it should be stopped and checked in time.Pay attention to safe production.

4、In the normal production process, the die caster must execute the correct die casting process requirements:

⑴Spray correctly.

⑵Brush oil on the relevant sliding parts on the mold.

⑶Clean the residual aluminum slag products or any other foreign matter on the parting surface.

⑷Control material temperature.

⑸Control mold temperature (with mold temperature machine, mold cooling water or spray).

⑹Control handle thickness. And according to the product quality, adjust the process in time.

5、In the die casting process, special attention should be paid to the mold cavity, parting surface and exhaust slot of the scum is clean, absolutely no residual aluminum slag or any other foreign matter.Try not to use hard tools such as file when cleaning, in order to avoid damage to the cavity surface, also to prevent mold failure, so please use air pump gun or copper rod tools to work.

6、In case the casting fails to come out or the casting is partially stuck in the cavity of the moving and static model, it is strictly prohibited to use a hard file or a power drill to remove it, so as to avoid damaging the mold and causing production stop-production failure.If there are more than one neutron core on the mold structure (neutron refers to the core moving by external force (oil cylinder connection) in the mold), and the core (pin) has interference with each other, you must be in strict accordance with the designer set the sequence of the core extraction or closure.

7、Mold in production and use for a period of time to tighten its components and effective mold maintenance, so to often keep mold parts clean, and remove the accumulation of aluminum debris and dirt on the moving parts, especially on parting surface, cavity, core, exhaust block, overflow tank more serious.Because the mold cavity surface in the die casting production molding process will often decompose low molecular compounds to corrosion mold cavity, so that the bright mold cavity surface gradually become dull and dull and reduce the quality of the product, so it needs regular cleaning and maintenance.Cleaning can be done with diesel or spark oil.After washing, dry the mold in time, and then paint the oil mixture inside the mold, so as to ensure the long-term effective use of the mold.

8、When starting up again after temporary shutdown, the slider limit of the mold should be checked to see whether it moves or not.After a period of mold production, to the mold and die casting machine connection of the fixed platen fastening inspection, to prevent falling off.

9、In the normal production process, regularly check the casting quality as required, and make relevant records.In case of any abnormality, repair or replace the mold in time.

Fifth. Reference for die casting process debugging (download from the Internet)

1、The purpose of focusing on weight as a reference element is to focus on the concept of compactness.The degree of compactness is different under different conditions, so we need to look at this point reasonably.

2、Generally speaking, if the surface of thin - walled castings is to be done well, the injection velocity must be fast. Thick wall surface to do well, the process of shooting must be strong.

Thin - walled surface to do a good job, the injection rate of the conventional machine is basically ok.For thick wall parts that require both surface and compactness, in addition to fast shooting speed, it is also necessary to ensure the inner compactness of the casting. During die-casting, after the explosive power of the two-speed nitrogen cylinder, the pressure supplement of the conventional machine may be insufficient.

In fact, speed and force are inversely proportional, like a car, low gear, the force is the largest, high gear force is not strong.Therefore, for thick wall parts with required surface, if there is a force supplement in the forming process, it can be better to assist the force this element, powerful and speed, compactness will be better.

Combined with the actual situation of die-casting, the relationship between force and speed, the engineer added the supercharging action to the machine to make the machine have this characteristic.Of course, reasonable excellent mold is the main part of improving the product excellent rate, the machine and skilled operators play an important auxiliary role.

3、The concept of force and speed for castings with different thickness and thin wall is clear, and the good standard of castings can be treated reasonably if the key points of each process are properly applied.

4、The sprue sand hole of thick wall products is usually caused by shrinkage hole caused by too high mold temperature. Under the condition that mold temperature control is not ideal enough, if the follow-up supplementary force is enough, it can make up for the sand hole to some extent.

5、Division of thick and thin wall parts: generally, the wall thickness below 3 mm can be considered as thin wall parts, while the wall thickness above 3 mm can be considered as thick wall parts. The 30 - wire surface of the casting is of good density.

Sixth. Instruction after production operation

1、When temporary shutdown is required, the mold should be closed so that the cavity and core are not exposed to prevent accidental damage.Downtime is expected to be more than 24 hours, in the cavity, core surface should be anti-rust treatment, especially in the wet area and rainy season, even a short time to do anti-rust treatment.Because the moisture in the air will make the surface quality of the product quality.When the mold is used again, the grease spots on the mold should be removed and cleaned before use.

2、When the production quantity of the mold has been completed and other molds need to be replaced, the following work shall be completed before the machine is shut down:

⑴Turn off the cooling water first

⑵Blow the excess water in the water channel of the mold

⑶The oil in the cylinder used for core pulling should be emptied as far as possible and the oil nozzle should be sealed to avoid leakage of hydraulic oil or pollution of the surrounding environment during storage and transportation.

⑷All moving parts, parting surface residual aluminum slag products or other foreign bodies must be removed clean, clean and on the product part, each moving parts, parting surface oil protection or spray anti-rust agent.

⑸Fill in the relevant records truthfully, send the accessories of the mold to the maintainer, and attach the qualified products of the last mold to the inspector as samples

Seventh. Use of mold cooling system

1、When used correctly, the cooling system can prolong the service life of the mold and improve its production efficiency.In the actual production we often ignore its importance, production operators in order to save time, also do not go to the cooling water pipe.Some companies even in order to save the cost of custom mold even do not need cooling water, resulting in a very serious shutdown.The material of the mold is generally special mold steel, is made after a variety of processing.But even the best materials have their limits.If the mold temperature is too high in the production, it is easy to make the mold core surface early turtle crack, some molds have not even produced more than 2000 mold cracks on a large area.Even in the production of the mold, because the mold temperature is too high, the mold core has changed color, and even reached more than 400 degrees after the measurement, such a high temperature and spray release agent chilling will make the mold large area cracking or serious cracking, casting is easy to deformation, strain, adhesion or scrap.

2、Under the condition of using cooling water system (water or oil), the mould can greatly reduce the dosage of release agent and shorten the long spraying process.Its advantage is to save the die casting production cycle, improve the quality of products, reduce production stop-production failure and die damage events caused by mold cracking or casting strain, aluminum sticking and mold sticking.It also reduces the loss of ejector rod, casting pin and mold core caused by the overheated mold temperature, and effectively prolongs the production life and production quantity of the mold.

3、Pay special attention to the use of cooling water system caused by the cooling pipe blockage, to check frequently.

Eighth. About the processing of flying material and adhesive mold on parting surface of mold

The mold is composed of moving mold and fixed mold.

Parting surface refers to the part that can be contacted when the two are closed.According to the requirements of mold production, the parting surface of the moving and fixed mold core should be 0.15-0.35mm higher than the parting surface of the mold frame (mold frame) to prevent the parting surface from flying materials.

1、It is generally more machine problems that new mold parting surface large area and local parts of the problem of flying material

⑴Clamping force is small and not locked in place.(empty lock for many times, check the locking strength)


Is the supercharging pressure too high?Is the trip too short?

⑶Whether the holding time is too short.

⑷Is it too warm? (normal position 660° ~ 680°)

⑸Check die casting machine for wear of curved core (curved arm) or bushing.Is the gap too large?

⑹Whether the machine wall is balanced

2、The mold will also have problems.

⑴The mold is not in place. (apply red powder to the smooth and easy to check parting surface of the moving mold core, and (generally apply it to the parting surface of the mold core) after the mold locking, check whether the red powder traces of the parting material surface not applied reach the production requirements of 95% or more.

⑵Die core exhaust location smaller, shorter or deeper (-0.15mm or more), easy to fly

3、 Mass production (more than 25,000 times) of mold parting surface flying material (old mold)

⑴Check whether the flying material position of parting surface is collapsed, the exhaust groove is too deep or there are foreign matters, such as aluminum slag is not cleaned, so that the mold can not close in place to produce flying material.

⑵Check whether the height of mold frame (mold frame) and mold core parting surface is in place.

The normal closing die is: the upper and lower parting surface of the die core meets each other, and the upper and lower parting surface of the die frame has a gap of 0.3-0.7mm.

Long time production products mold deformation, die box around the edge of the upper and lower parting surface hit dead or obviously adhere to foreign bodies, so that the mold core upper and lower parting surface can not touch, can not match to the effective position, resulting in the gap will have flying edge, flying phenomenon.

Ninth.  About the treatment of products yellowing and blackening (Internet download)

 All the time, the aluminum alloy die casting cleaning is always a difficult problem. The practice of many enterprises is, after machining, do not do thorough cleaning, just use water to simply rinse, then blow dry, or even natural air dry, and then stacked in the warehouse for a few months.Suddenly one day need to be out of the warehouse, only to find the work piece long mildew spot, moldy, black, yellow situation. At this time, we suggest you: 1, with die-casting aluminum mildew spot cleaning agent timely and thoroughly clean, including the surface of the work piece oil, slight oxidation mildew point (mildew point is still very small, do not look carefully, the naked eye can not really see); 2, after cleaning, immediately do an anti-oxidation treatment. It should be noted that currently chromic acid has been banned, the use of chromium and cyanogen free passivant to meet the environmental requirements; 3. After anti-oxidation drying, the workpiece shall be placed in a dry and ventilated place and inspected regularly.

Tenth. Fragile workpiece


Replacement time


Ejection rod

At any time

Deformation, fracture, fluff, abnormal sound

Cast pin

At any time

Deformation, fracture

Irregularly shaped insert

At any time

Deformation, fracture

Seal ring

At any time

Leaks, breaks, expiration date

Rubber tube

At any time

Leaks, breaks, expiration date



Replacement time

1、Vulnerable workpiece according to the mold production product strain, deformation, fracture, uneven or mold production abnormal sound failure, please replace at any time

2、If it is damaged during assembly or production, please replace the required workpiece at any time.






First Western Building,Yanshan Industrial Park, Bengshan District, Bengbu City,Anhui Province
Longhua Die Casting Machine Co., Ltd was founded in Bengbu, Anhui Province, China. It is a professional high-tech enterprise engaged in design,manufacture and sale of cold chamber die casting machines and die-casting peripheral equipments.


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