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how to improve quality control

by:Mingquan Machinery     2019-12-11
What is quality control?
Quality is defined as building things and providing services according to the requirements set by the customer.
Each metric is a variable that should ideally be within the desired range.
Quality control is the process of keeping these variables within an acceptable target range.
The work of quality control is to set these acceptable ranges for each variable, identify products that are out of that range, and rework products that do not meet the quality standards.
How to evaluate quality control?
According to the fifth edition of the Maynard Industrial engineering manual, there are four evaluation criteria for quality control: quality standard, quality target, quality level and inspection standard.
When measuring the quality, the quality standard is the highest and the most ideal.
Quality standards are what customers and designers want to see.
The inspection standard defines the goods that are allowed to be shipped to the customer and the goods that are sent back as scrap or rework.
The quality level is established by the internal supply chain.
The quality target is the lowest quality evaluation standard;
This is the quality produced by the production line, including unqualified products.
When the result of quality control is not as high as the management or the customer wants, you can take some steps to improve the quality control.
How to improve the quality control of the workshop is most effective in the early stages of the manufacturing process, rather than wasting further manufacturing efforts on the bad part.
Determine where the defect occurred and where it was captured.
Ideally, once a defect occurs, your quality control process will find the defect instead of letting the product move further downstream.
If the defect is caused by a specific machine, please transfer the inspection to so that the product is checked as soon as it is out of the machine.
Use inspection and correct quality control methods at each workstation, instead of allowing defective products to reach the post-manufacturing steps that could lead to disassembly of components.
Record as many defects as possible in order to record all relevant information and contributing factors fresh in the mind of the recorder.
Simple defect reporting and data analysis can be accessed using the data recording function in the workshop data management software or other online tools.
Ensure process data is captured correctly and completely.
\"Six Sigma is unveiled: Self
Paul Keller\'s teaching guide notes that process data may be the most abundant and reliable source of information for quality control decisions.
Standard operating procedures are used to reduce the source of human variation in the manufacturing process.
Use automatic inspection and testing to reduce human negligence during inspection and testing.
Production control should be part of quality control.
Make sure the personnel have the latest drawings and the correct procedures for the parts they are building.
When the product portfolio changes, verify that the device is following the correct procedure.
Make sure that the SPC data and acceptance/rejection criteria are for new products and not for old ones.
Maintain your equipment.
When the tools are worn, they begin to produceof-Specification components.
By checking and repairing the equipment, you may be able to improve the quality level better than the components that have been inspected and repaired.
Set up a quality circle for each production line or working group.
Let employees make suggestions to improve the quality of the products and make the quality control work easier.
Balance production objectives and quality.
Demand for speed affects quality.
When the device monitors the quality-related variables in real time, regularly check the sensor and device to ensure that it works properly.
Ideally, sensors and hardware are inspected and calibrated by independent third parties so that employees do not intentionally or inadvertently change the settings of QC equipment, affecting the results of the process.
How to improve quality control through supply chain quality should start from supply chain.
Variable raw materials increase the variability of manufacturing process output.
Regardless of the supplier\'s quality grade, check the quality of your incoming materials on a regular basis.
You can\'t accept the supplier.
Work with suppliers where possible to improve their quality level.
Always report to the supplier the issues you have tracked so that they can solve their quality problems.
Timely manufacture of instant delivery dependent on supply.
The production line can get what it needs as long as it needs it.
This makes the quality of the supplier essential because the production line stops working when incoming parts do not meet the quality standards.
If your production line is running in JIT mode, choose a higher quality supplier instead of a lower cost competitor, because the lack of quality components will cause the production line to be idle.
The quality control test will verify the quality when the product is manufactured.
If the product may deteriorate during storage, you may want to prove that it is good before shipment.
It may be necessary to ensure that the quality is not affected by shipping or processing on the way to the customer.
Verify that all suppliers meet the new quality standards before implementing it on their own.
How to improve the quality control of new products through quality control plan management should be developed as a manufacturing process.
Determine how to reduce and monitor process variables when designing a manufacturing process.
Test the quality control process and inspection method as the production line accelerates.
Ensure that new Assembly personnel are trained to identify and record defects when learning to assemble new products.
When you change the manufacturing process or quality standard, please update the quality control plan.
Then communicate the facts of the new process or without any change to your employees.
The quality control plan is measured by the number of bad parts and the number of false positives they capture related to the parts produced, and the number of good products accidentally identified as bad.
Check your quality control plan on a regular basis to determine how many bad products it has passed and how many good products you unnecessarily mark as not meeting the quality standards.
Organizations can improve the quality control of the whole organization by establishing a quality control system.
What is the quality control system?
In order to ensure that there is no defect in the product and the process of manufacturing the product, there is a quality control system.
Quality control is an indirect cost that is expected to be offset by reducing rework, returning products, losing sales due to poor product quality and paying higher prices to customers who want higher quality products.
Quality control is best achieved when the quality system is in place, so quality is a consideration for every step of the manufacturing process from procurement to product delivery.
In addition to implementing some quality control methods, establishing a quality control system is one of the best ways to improve quality control in an all-round way.
How to improve quality control through engineering and design engineers, quality should be kept in mind.
Design parts that are easy to manufacture and assemble, thereby reducing manufacturing and assembly errors.
Design components that are easy to test in order to test more components using the same number of inspectors.
Tightening the part tolerance can reduce the interference problem and loose connection.
However, increasing the tolerance of the part by one decimal point is said to increase the manufacturing cost by ten times.
For example, the cost of producing mm tolerances is ten times that of parts with tolerance plus or minus centimeters.
Balance the cost of more accurate tolerances compared to other methods to improve product quality.
Changing design tolerances can change the quality control practices of the workshop, so more precise sensors or new QC verification tools are required to be purchased.
Quality control requirements require coordination between different groups such as suppliers and standard organizations.
Eliminate redundant inspections and overly accurate quality measurements.
Determine if different QC teams can share data in the existing QC process instead of relying on secondary checks.
For example, can the supplier check the process before shipping so that your company does not have to perform incoming QC?
Is it acceptable for the customer who received your Assembly to accept your quality data instead of checking the parts again?
If the part has recently finished final quality control on the assembly line, do you need to check before installation?
Review quality standards and customer requirements against those really important variables.
Monitoring is no longer good for metrics that are important to customers or cosmetic products and not functional, unless beauty is customer care --about.
Verify that alternative parts and materials meet the quality standards before they are approved for use in the production process.
Engineering Approval and thorough testing are required before new replacements are allowed.
When you are on a tight budget, how to improve quality control and identify key to quality, critical to progress, and critical to cost variables as an indicator of the record.
If your business resources are limited, these are the process variables that need to be improved first.
For example, if the customer complains about the poor installation of the protective housing, it is not good to use the resources to improve the testable nature of the product.
When the resources of an organization are limited, focus on the burning platform before you try to do something perfect.
Focusing on prevention is more valuable than checking because preventing defects can prevent rework, repair, waste of materials and even greater inspection costs.
Measure the process capability of the manufacturing process.
How many products do they produce that meet your quality standards?
If the normal distribution of the production line produces a significant percentage that exceeds the specification, you want to improve the base manufacturing process instead of investing in more inspections or tests.
When choosing a quality issue to be addressed, the desire for the most common defects will be balanced against the defects with the highest cost of repair or those that violate the customer\'s expectations for product quality.
Be careful to find out the real problems and the real reasons.
If the employees with the worst quality of work are new, the root cause may not be the employees, but the training they receive.
If the product quality of the night shift is worse, is the working conditions, environmental variables or other factors of the night shift the real root cause?
If you don\'t have a real root cause for the problem, you will invest the money in an incomplete solution.
How to improve quality control by using the right tools for work according to S. \'s \"corporate management, governance and ethical best practices\"
Rao Vallabhaneni has seven original quality control tools.
These QC tools are checklist, histogram, scatter plot, Pareto chart, flow chart, cause and control chart.
If not for centuries, these quality control tools have been around for decades.
There are seven major quality management tools that are more modern inventions, says Vallabhaneni.
These major quality management tools are affinity maps, processes-
Decision program diagrams or matrix diagrams such as PDPC, quality function deployment matrix, mutual diagrams, tree diagrams of all types, priority matrices, and active network diagrams.
However, it is estimated that there are more than a hundred quality control tools and methods available for use.
Use the right quality tools for work.
Use a checklist to identify the identified problem.
Use experimental design to find out the root cause.
Error Prevention will only prevent future defects.
Control charts and process logs can help you identify major issues, suggest root causes such as high failure rate times, and verify improvements in quality control.
The revised flow chart shows current issues and production trends.
Statistical process control is one of the few quality tools to support all problem solving cycle steps from problem selection to correction to verification and prevention.
Use running charts instead of bar charts to display process variables so that changes over time are clearly displayed.
Running the chart will show the change over time, while the bar chart shows the total.
Although the two production lines may have the same average, processes with much greater variability are not controlled and will produce more outputof-
Product specifications are slightly-
Not average, but the change is small.
Automated Defect data collection makes data mining a possible tool to improve quality control.
However, data mining itself may not be enough.
Six Sigma: Self-Liberation
Paul Keller\'s teaching guide says data mining can be used to identify opportunities for improvement, but it may not provide enough information to decide how to address potential quality issues.
How to improve quality control by changing the corporate culture recognizes that rework is a waste of time and money.
This is better than shipping defective products or scrapped components, but organizations need to focus on the plan --Do-Check-Act or Define-Measure-Analyze-Improve-
Control the process improvement method, eliminate the root cause of defects and improve the overall quality.
No matter what kind of quality improvement method is selected, it should be implemented in the enterprise --
A wide range of scale has a lasting impact on product quality.
The most important thing is to choose a process improvement method, train everyone to use it and provide sufficient resources to improve the quality at all levels of the organization.
Make quality a part of corporate culture.
If quality is everyone\'s job, from the maintenance technician of the production line motor to the CNC machine programmer, employees are more likely to give suggestions to improve the quality of the product and report problems that affect the quality. References1. \"The Step-by-
Larry P. Step Guide to Measuring cost and risk of poor quality informationEnglish 2.
\"Six Sigma is unveiled: Self
Teaching Guide by Paul Keller 3.
D. Six Sigma and beyond: problem solving and basic mathematics, Volume 2H. Stamatis 4.
Best practices in corporate management, governance and ethics\"
Rao Vallabhaneni army.
Anna C. change risk management: focus on quality improvement in product development and productionThornton 6.
Maynard Handbook of Industrial Engineering, 5 th editionZandin 7.
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