Inspection accepts the manufacture of non-conforming product and acts as a filter to remove it from the production flow. (Reactive system)
Quality Control attempts to prevent the manufacture of non-conforming product in the first place and attempts to predict, reduce, or eliminate the causes. (Proactive system)
Inspection is merely checking an item with respect to the specification, quality control is deciding about acceptance / rejection , whether specification is too stringent, is there any possibility of correcting the rejected items.......
Refer thread286-63405 for discussion on QA, QC and testing
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inspection can be part of QC.
Quality Control is making sure that you get the specific quality that YOU want.
Inspection can in be a part of the way to make sure you get that quality.
Inspection is some method of looking at something to see if that thing (installation, machinery, you name it) functions correctly, if it is made according to the specifications (here comes your QC again.
With inspection you try to lokate problems in the installation before the breakdown occurs.
And there are many kinds of inspections:
just to name a few:
Preventive inspection
Inspection prescribed by the law
Dammage inspection
If you want to know more about inspection, please let me know.
Inspection is a process to measure some variable or attribute of some product. Inspection can be as simple as checking for scratches or dents to measuring dimensions or surface texture or coating thickness or finally doing sophisticated laboratory analysis. Inspections can occur during a process such as gaging during an OD grind operation or inspection of a hydraulic valve spool bore during a honing operation. Inspection is many times part of the process to make the part. It is value added in those situations.
Quality is relative. One customer has different expectations from another. Say you are making 10,000 units of a product which uses ten of a particular value resistor. The manufacturer assures you there is 1 part in a million which is bad so you have a 1 in 10 chances of having one assembly in 10,000 with a bad resistor. If you are making televisions the risk is probably acceptable. What if you are making the control circuits for a nuclear bomb. Is the screening for that 1 in a million value added?
I have actually seen a robot inspection station 100% inspecting resistors in a nuclear trigger facility.
Quality control used to mean the QC department approved parts after manufacture. Typically there were QC inspection stations which inspected a batch of parts after manufacture and either rejected or accepted the parts.
Quality assurance does still do inspections but their main goal is to assure the process of making and checking parts is followed during manufacture. Both QC and QA have calibration of gage responsibilities and liaison responsibility between engineering and manufacturing.
QC or QA titles are mostly based on the history of the company. Almost all QC and QA departments are now quality assurance departments as they have insuffecient staff and resources to do quality control.
Quality Control is a system/program of verfied/documented checks to prove compliance to the requirements. The requirements may be in-house, Customer, Codes/Standards, etc. QC is reactive.
Inspection is the task of determining conformation. This may involve many different methods: visual, NDE, sampling, etc.
Quality Assurance is a proactive, documented, auditing system to ensure the causes of nonconformances or noncompliances are eliminated.
Quality is measured by a degree of compliance of the product to the given set of requirements.
Qulity is achieved by a combined set of actions:
Quality Control and Quality Assurance.
Quality Control (QC) focuses on the product. It will comprise of inspection, testing both destructive and nondestructive. QC provides feedback to the system on the quality of the product. Any non-conformance to the requirements should triger correction, and corrective action.
Quality Assurance (QA) deals with the system managing the quality. Upon receipt of the feedback sytem trigers changes to itself.
Therefore QA and QC go hand in hand denspite the fact they mean something totally different.
I agree QC is reactive but it provides data to the proactive QA.
Inspection is an important QC function but not the only one.
Quality Control is a hierarchical plan that demonstrates how conformance is managed during various tasks and subtasks to achieve a desired goal. (Refer to ISO-9001) The conformance is assessed against international standards, regulations, client data sheets else manufactures own specifications. As an example: the conformity of the following items are addressed in a Quality Control Plan.
a) Positive Material Identification.
b) Dimensions & Tolerances
c) Material chemical & mechanical properties
d) Heat treatment
e) Surface Preparation
f) Proof testing
g) Fabrication quality & Assembly
Inspection is a series of methodologies used to verify the degree of conformance. In practice, a quality control plan has various conformance requirements and corresponding inspection activities. (Refer to International Standards, items under Inspection & Testing. As an example: the following items are inspection activities:
Your question is quite a bit out of topic but I will try to answer it. In accordance with En 10204 3.1.C certification shall be issued by third party. In some jurisdictions that third party shall be a government agency. The third party does a complete review of the product (e.g. material verification) and witnesses all special processes and tests. At the end the data dossier is reviewed and release note/3.1.C certificate is issued. In the case of 3.1.B certification the QA/QC manager of the manufacturer issues the certificate. I ma not a rotating machinery specialist and will not be able to prescribe all the required tests for the compressor, but these should be specified in th epurchase order. Just make sure the Third Party Agency gets engages early enought to be able to certify the equipment.
Some very good discussions here, although I would tend to agree with VeryPicky's explaination! I have been in the inspection industry for over 20 years and have frequently asked other Quality professionals to explain the difference between Quality Control and Quality Assurance.
I was amused to find that nearly everyone had a simular but different idea. Perhaps what is important is what it means to the people paying for it! Just a thought!
To begin with inspection is on both sides of the equation both QA and QC, however the difference the charter you’re given. One is to setup a system to minimize and respond to nonconformities so that they don’t flush the profits down the drain, and it is proactive where you put in place systems for prevention and train all involved so that they are able to recognize problems and instantly respond thus nipping problems in the bud. The customer normally utilizes the other too give them a piece of mind that you are doing your job.
I have been involved in quality engineering since 1982 and I have a BS in Manufacturing Engineering also an AAS in Test Engineering.
