Die Casting Workshop Production Process Quality Control Methods

diecast workhop1

In any die-casting enterprise, there is always a choice between quality and quantity when facing the production season. Either seek the momentary profit and ruin the development of the enterprise’s future or consider the quality carefully cultivated. If the quality of the product once a problem, it will not only increase the rework and the additional cost increase but also be caused by customer complaints, which directly affect the economic efficiency of the company and damage the reputation company. Therefore, it is imperative to strengthen the quality management of the production process.

Table of Contents

Alloy melting

1.The temperature of the melting furnace should be controlled at 630℃-680℃.

2.observe the melted aluminum, suitable for the production of aluminum, is bright white; if the aluminum is red, indicating that the furnace temperature is too high, such as if aluminum is ice cream-like, the temperature is too low.

3.It is strictly forbidden to mix impurities in the process of melting aluminum, forbid operators to put unqualified products into the furnace back into refining, such as products need to be back into the furnace re-refining, must be confirmed by the team leader inspection, before being put back into refining.

4.Keep the liquid level of aluminum smooth, with no slag and bubbles; when scooping aluminum liquid for die-casting, you must scrape the oxidation layer and impurities on the surface of the aluminum liquid.

5. production process, each shift must be refilled twice in the furnace powder refining agent and de-slagging agent, an average of every 4 hours refilling. The entire refilling process must be carried out under the guidance of the team leader. After the operation completes, the impurities generated by refining must be cleaned up before casting production.

6.During the production process, the bottom of the furnace must be cleaned at least twice per shift, at least once every 4 hours on average.

7.all tools in contact with the aluminum liquid, must first dry to keep dry and clean; impurities cannot accompany them in the aluminum liquid.

8.In melting aluminum, if too many impurities are found in the ingot or furnace material, it should be stopped immediately, and put the same kind of ingot or furnace material should go into the furnace again and report to the shift manager and workshop director in time.


Mold loading

1.First of all, ensure the accuracy of the mold type and the integrity of the mold.

2.The mold assembly should be done with the mutual assistance of the operator, maintenance worker, and team leader.

3.When assembling the mold, ensure each solid piece’s solidity to ensure the mold’s safety in the production process.

Mold debugging

1.After the mold is assembled, the machine can be tested (pointing), and the automatic low-pressure air run for one week to ensure the flexibility of the assembled mold.     

1) Check whether the screws are loose.

2)Check if there is any oil leakage or other abnormalities in the equipment.

3)Check whether the moving parts of die-casting machine and mold are refilled with lubricant.

2.Temperature of the mold (mold preheating)

1)Temperature of the mold surface is warmed up to 180℃-220℃.

2)Check whether the cooling water is running normally.

3.Trial die-casting

1)The team leader sets the die-casting parameters.

2)Check whether the aluminum liquid to be cast is applicable.

3)Observe whether the equipment and mold run normally when die casting.

4)Check whether the mold release agent’s spray pressure and water volume are normal.

5)Check whether the die-cast product’s size and appearance meet the drawing and inspection card requirements and whether there are any product defects.

6) Test die-casting products must be more than 50 pieces (must play low-speed die-casting 20 die, then open high-speed die-casting test).

7) final confirmation of qualified die-casting, which can be retained as the first inspection products, and fill out the “first inspection sheet.”

aluminum die casting mold

Die-casting production

1.After the die-casting products are confirmed qualified, the parameters set shall be determined, and the operator shall not change the set parameters without authorization.

2. the production process, such as the discovery of equipment abnormalities such as abnormalities or castings left in the mold, should immediately stop and notify the maintenance personnel, the operator is strictly prohibited from private maintenance.

3.During the production process, the operator should ensure the reliability of the mold.

1) Due to the uneven parting surface or more wear, the clamping force is insufficient, resulting in more castings with flying edges.

2) Aluminum splash at the injection position due to punch wear.

3)Damage to the die cavity and slider due to misoperation.

4) Due to the long-term use of the mold, prompting mold material fatigue, resulting in chipping damage, affecting product quality.

4.the production process, the operator should do product self-inspection, the provisions of each die-casting molding 20 pieces of products, that is, a self-inspection of the product, such as the discovery of product abnormalities, should immediately stop production from finding the cause.

1) Due to the low temperature of the mold, the low temperature of an aluminum liquid or slow filling speed of liquid aluminum results in the hard partition of casting.

2) Due to insufficient holding time, the casting mold slope is too small, leading to casting or even pulling cracks.

3) Due to the deviation of aluminum liquid material, the rough surface of the mold cavity, an insufficient amount of mold release agent, or failure, resulting in castings sticky mold.

5, in the production process, if the mold is found to have slight chipping, and the casting only needs to be repaired in appearance, does not affect the performance, need to report to the team leader and workshop director promptly, handling methods are as follows.

 1)According to the current situation, production can not be terminated, but the castings must all be repaired; after the batch of products die-casting is completed, the mold must be repaired; the situation applies to the batch of small products.

 2) immediately stop the production, disassemble the problematic mold for repair after repair, and test die-casting to confirm its integrity, before continuing to put it into production.

Mold release agent

1.Before making die-casting in the production process, the mold must be sprayed with a mold release agent.

2.Check whether the release agent spraying air pressure is suitable for die-casting production.

3.Check whether the flow of the release agent is suitable for production.

4.Check whether the mold release agent fails.

5.If the above problem occurs, the team leader and workshop director should be notified immediately. The injection air pressure, flow rate, and release agent ratio should be adjusted in time until it is suitable for production.

Production Inspection

I.Confirmation and assembly of the mold

1. the team leader must confirm the conformity of the mold model to be used for assembly, and the product model should be consistent with the production order.

2.The team leader must confirm the integrity of the mold to avoid chipping and damage to the mold installed in production.

3.For the assembled molds, check their tightness and fill the lubricating oil to ensure the flexibility of mold operation.

4.It is necessary to confirm the conformity of the mold test die-casting products.

II.the first inspection of the product

1.The team leader must confirm whether the first die casting produced meets the drawing requirements.

2.the team leader in the first product inspection must confirm the die casting size appearance and other conditions to meet the drawings and inspection card requirements.

3.The team leader must confirm the good operation of die-casting equipment and molds when conducting the first inspection of the product.


1.The team leader will inspect each running equipment at least once every hour to correct the bad operation of the operator.

2.Inspection of each machine and random inspection of the products being produced to confirm the conformity of the products immediately.

3.The team leader should deal with the production abnormalities that occurred promptly, and major quality problems should be reported to the workshop director promptly.


1.The team leader should verify the handover procedures and record them during each shift changeover.

2.The team leader should fill in the work diary to record the shift’s quality problems and production situation and work tips for the next shift.

Quality control

I.Full inspection of products

1.The inspector carries out the complete inspection of the die-cast products.

2.Mainly inspect the product’s appearance, defects, and other items.

3.In the full inspection process, if the product has any quality problems, the team leader and workshop director should reflect on the situation in time.

4.The whole inspector should record the quality problems of the inspected products.

II.the product sorting

1.The whole inspector should sort the inspected products and resolutely eliminate the unqualified products.

2.The unqualified products rejected in the whole inspection process are classified, isolated, and marked according to different quality problems.

3.Different types and models of products must be placed differently to prevent different products from mixing.

III. the product identification

1.The products that have been fully inspected must be marked, and different types and models of products must be distinguished.

2.In the product identification, the product model, type, quantity, die-casting machine number, operator’s name, and full inspector’s name must be indicated.

3.The unqualified products must be marked and isolated to prevent the selected unqualified products from being mixed into the qualified products again.

Sampling inspection of products

I.First inspection of the product

1.Quality inspector must participate in the first inspection of the first product.

2.Quality inspector must confirm that the first inspection products fully meet the requirements of the drawings before continuing production.

3.For the products that fail the first inspection, the quality inspector is responsible for asking the operator and the team leader to adjust or repair the equipment and molds until the qualified products are produced.

II.the product inspection

1.The quality inspector will inspect the products being produced in each department at least once every hour to confirm whether the products being produced meet the drawing requirements.

2.The quality inspector will inspect the products being sorted by the full inspector once every hour to confirm whether the products being inspected are following the drawing requirements.

3.in the inspection process, the substandard products should be immediately marked isolated; quality inspectors are responsible for urging operators and team leaders to correct this.

4.In the process of inspection, if significant quality problems are found, or serious potential problems are found, they should be reported to the workshop director and quality department immediately to facilitate timely processing.

5.in the inspection process, such as equipment, mold, and other issues that can be repaired due to minor quality problems, quality inspectors should promptly notify the workshop director and quality supervisor. Such cases, such as in the aftermath of the repair, can be solved and continued production. After the batch production is completed, the relevant personnel should be notified of the timely repair of equipment and molds.

III.the final inspection of the product (random inspection before entering the warehouse)

1.The quality inspector will make the final random inspection of the products before entering the warehouse.

2.The inspection of product performance size and appearance is carried out according to the production drawings.

3.For the unqualified batch products, the actual situation can be scrapped, reworked, sub-inspection, and other processing.


1.Responsible for the testing, acceptance, and filling of testing records of die-casting molds and timely reporting of relevant “Quality Daily Report.”

2.Responsible for the process control of the workshop, responsible for the first inspection, inspection, and warehouse inspection of the products, and filling in the relevant inspection records.

3.Responsible for the final inspection of the products into the warehouse (out of the warehouse) inspection, unqualified products are not allowed into the warehouse (factory).

4.Supervise and check the work of part-time and full inspectors, coordinate and deal with quality problems in this workshop.

5.Responsible for keeping the quality inspection records of the workshop to assist the workshop in dealing with customer returns.

6.Assist the workshop in putting forward product quality improvement plans to improve the level of the made process.

Process control should be noted in other issues

I.the key processes should be focused on control.

II. for the core of the long easy-to-cause product deformation of die castings, operators, team leaders, and quality inspectors should strengthen their inspection efforts and, as a priority, ensure that qualified products flow to the next process.

III.the process completed semi-finished products, in the full inspection, can not be stacked too high. Different products with similar shapes and different specifications need to be marked with effective product placement between different products to prevent significant confusion between different products due to the close distance in handling, moving, and production process.

IV.the control of non-conforming products

1.During the production process, if the die-casting product is unqualified or the mold is damaged, the finder should report it immediately. The team leader, quality inspector, or workshop director will organize to mark and isolate the unqualified products and place the unqualified products in the designated area.

2.In the inspection link, the unqualified products appearing such as can be solved through technical processing of the relevant quality problems, the full inspector and the quality inspector can request the production line to make technical processing. After processing, the product must be re-inspected.

3.The non-conforming products found, the workshop quality inspector fills in the “Quality Report” and reports to the quality supervisor. The quality supervisor will call the relevant workshop personnel to analyze the unqualified products and make a written decision on the treatment.

V.The quality inspector can summarize the quality status of the workshop production once a week or once a month, covering product quality, customer returns, customer quality complaints, etc., and report to the quality supervisor, who will make the final monthly quality report.

Raw material testing, testing, batch number management, and the timeliness of the die-casting processing

I.raw materials (aluminum ingots) testing and test die-casting

1.All incoming aluminum ingots must be tested in the physical and chemical room, and only the qualified ingots can enter the die-casting workshop for trial die-casting.

2.Newly arrived aluminum ingots that have not been tested can be temporarily stored in the warehouse first, and the warehouse manager should strictly distinguish the new ingots from the nuggets in use, mark the new ingots temporarily stored in the warehouse, and mark the same number of nuggets in different piles of the same batch.

3.The ingots temporarily stored in the new warehouse are not allowed to be issued to the production workshop for use without permission. The identification of the batch of aluminum ingots. There should be a clear code of material alloy, quantity, date of purchase, and state of inspection of the ingot (the new ingot in the warehouse without laboratory test and test die-casting must be hung with the sign of pending inspection).

4.After passing the laboratory test, the ingots must be tested die-cast in the die-casting workshop. The test die-cast products cannot be less than 2000 pieces for small pieces and 800 pieces for large pieces. The test die-cast products must be inspected by the workshop director and quality inspector of the quality management section. They must be inspected after aging treatment, such as cracking, cracking, deformation, etc.

5.After the laboratory test, test die-casting, and aging treatment inspection are qualified ingots, the quality control section quality inspector fills in the “Ingot Inspection Report” before confirming suitable raw materials. According to the above inspection report, the quality management section will sign and confirm on the “warehouse receipt” and indicate that the ingot has passed the above two inspections. The material can be officially put into the warehouse, and the warehouse manager will officially hang the inspection mark, indicating that the material can be officially put into production.

II. the timeliness of die-casting processing

1.All die-casting parts must undergo aging treatment to eliminate the product’s die-casting stress.

2.the die-casting workshop produced by the die casting, after full inspection, must be after 15-20 days of stacking, in order to eliminate the production of die-casting stress, in the aging treatment of die castings before flowing into the next process processing.

3.the aging treatment of die castings must be a clear time mark.

4.After the aging treatment of die-casting, the quality inspector should conduct a random inspection of the product. To determine whether the product fully meets the production requirements before the formal warehouse into the next process production.

5.If the products with unfinished timeliness treatment are activated due to urgent production needs, the quality inspector of the die-casting workshop shall fill in the “concession release order”, and must be approved by the company’s inspection section and the director of the die-casting production workshop.

6.When starting the products with unfinished timeliness treatment, the first product to be treated should be shipped first.

III. the batch number management of raw materials (aluminum ingot)

1. because each batch of raw materials (ingots) into the composition of differently, the die-casting workshop in producing raw materials must be batch number management.

2.The batch number ingots put into production must be those that have passed the inspection mentioned above.

3.The products produced by the same batch number of ingots must be strictly distinguished from those produced by other batch numbers and marked. The labeling includes product type, material lot number, production time (time mark for time-sensitive processing), etc.

4.Later machine processing also needs to be based on the material batch number.

The control of the furnace material

1.in the die-casting production process, the operator is strictly prohibited from putting back into the holding furnace material (such as defects in the product, slag collection package, etc.). The behavior of putting back into the furnace without permission is a serious violation of the production operating procedures and will be subject to economic punishment.

2.the operator in the production process, the unqualified products, slag material, etc., placed separately in a special basket, are strictly prohibited from placing the furnace material directly on the ground. All furnace materials should be stacked separately and marked.

3.die casting slag and sandblasting scrap material are strictly prohibited to put into the holding furnace. It must be melted, gas removed, slag removed, and refined before use.

4.back-to-the-furnace material should be concentrated into the re-refining; back-to-furnace material is suitable for back-to-the-furnace re-refining and needs to be tested before deciding. Furnace material should be sorted before re-refining to remove debris and other irrelevant materials. After sorting back to the furnace, the material must be cleaned to eliminate the impurities and dirt attached to it.

5.has been tested and qualified back to the material, the workshop director to decide when the back to the material into the re-refining, back to the product using that equipment for processing, production of what products (mainly non-gas-tight products and products with low strength requirements), etc… The production team leader and quality inspector monitor the input of reheat material into the furnace and strengthen the inspection of reheat material die castings (including strengthening the inspection efforts strengthening the sampling of products).

6.all back-to-the-furnace material die castings must also undergo aging treatment to eliminate the product die-casting stress.

7.all back-to-the-furnace material die castings must be marked.

8.Not return to the furnace to re-refine the treatment of scrap.

1)The scrap will be melted into aluminum ingots by the workshop.

2) After sorting when the scrap aluminum is for sale.

Die-casting equipment and mold maintenance and maintenance

I.Die-casting equipment maintenance and maintenance.

1. all die-casting equipment should be used strictly with the equipment operating procedures carried out.

2.For all die-casting equipment routine maintenance and maintenance, secondary maintenance, intermediate repair, and overhaul, please refer to the “equipment management procedures” to carry out.

1) Daily maintenance and upkeep of die-casting equipment, such as daily inspection of equipment before going to work, filling lubricating oil, etc., to ensure the normal operation of die-casting equipment.

2)Die-casting equipment running 1000H for maintenance.

3) The die-casting equipment runs for 6200H for medium maintenance.

4) The die-casting equipment runs 18000H for overhaul.

3.Establish the operation instruction for daily maintenance and repair of the equipment, and the die-casting workers will carry out the daily maintenance and repair of the equipment according to the requirement of the operation instruction before going to work every shift.

4.Each die-casting machine establishes an equipment file by each shift leader to record the daily equipment maintenance and equipment maintenance situation. Such as the type and quantity of products the equipment produces in the shift.

5.die-casting equipment at all maintenance and intermediate repair levels, overhaul, and other records composed of equipment-related files.

II.the die-casting mold maintenance and maintenance.

1.Every set of die-casting molds that are in use and newly made should establish a mold file.

 2.the old mold file should indicate the mold into use time, what has been pressed, how many die, and other data. The above data can be estimated as a value.

3.Establish the operation instruction for daily maintenance and repair of molds, and the die-caster, shift manager, mold worker, and maintenance worker will carry out daily maintenance and repair of molds according to the requirements of the operation instruction.

4.The operation instruction for daily maintenance and repair of molds should be clear in the following aspects.

 1) Who is responsible for installing the mold on the machine?

 2) Who is responsible for cleaning, inspection, and recording after the mold is unloaded?

 3)The maintenance of the mold.

 4)The service life of the mold.

 5.After the new mold is made, the quality management department will be responsible for convening the mold design and production personnel, the die-casting workshop director, the quality inspector, etc., for the discussion of mold acceptance. Qualified molds can be put into production; design and production personnel discuss unqualified molds for improvement.

6.The mold file should record how many products the mold has die-cast, what kind of problems the mold has produced, the maintenance record of the mold, etc.

The standard for measuring the merits of the production process is a high production, high quality, and low consumption. It can also be said to be much faster and better, and its quantitative index is reflected in the input-output ratio. In the production process, enterprise managers strive to produce as many products as possible to meet users’ needs with the least amount of labor consumption (including physical and living labor). It is to produce products that meet the company’s quality requirements at the least cost.


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