Quality Control



We have a good Quality Control set up for monitoring the quality of product starting from raw material to finished product.


Inspection at In-coming Stage:- After receiving the materials from supplier, those are inspected by our QC staff as per approved Quality Plan. If the materials are not acceptable, those are returned to supplier. Details of inspection are recorded in In-coming Inspection record.


Inspection at process stage:- During manufacture, products are inspected at process stage as per QAP and those are recorded in In-process inspection record.


Inspection at final stage:- After manufacturing of product, those are inspected as per approved QAP and those are recorded in Final Inspection record.


The following instruments are used for monitoring the product:-


  • DIGITAL VERNIER CALIPER
  • OUTSIDE MICROMETER
  • BORE DIAL GAUGE
  • INSIDE MICROMETER
  • PRESSURE GAUGE
  • STEEL SCALE
  • HYDRAULIC MACHINE FOR PRESSURE TESTING.

Statistical Quality Control application:-

    Statistical Techniques is applied for analysis Characteristics and trends of processes and products. For analysis of Process Variation X Bar R Chart are used.

    Statistical Process Control shall be conducted on the critical parameters to be identified by Quality Assurance In-charge.

    The selection of the components shall be based on their criticality. Works Manager shall be responsible for data collection and keeping the record.

    X-bar & R Chart

    X-bar & R Charts shall be used to monitor the critical characteristics during process and shall be evaluated using variable data. A minimum of ten rational subgroups (subgroup size 5) shall be collected from the on-going process for each parameter. The control limit shall be set in the following fashion :-

    For X-bar Chary: UCL = X + A2R where X = mean of average
    LCL = X - A2R R = mean of ranges
    (Range = max.-min.)
    A2 = 0.577 for sub-group size 5
    For R Chart :
    LCL = D3Rwhere D3 = 0 for sub-group size 5
    UCL = D4Rand D4 = 2.114 for sub-group size 5

The Control Limit shall be defined as per the above formula after sufficient collection has been one.Record of X-bar & R charts shall be available with In-Charge QA and kept in the file.


When the Control Limits are well within the specification limits, the lot shall be accepted. When the Control Limits exceed the specification limits, the lot shall be either rejected and this shall be decided by the I/C QA. Corrective and Preventive actions shall be taken in case of points lying beyond Control Limits.


Accepting Sampling Plan for final inspection shall be as per the Quality Assurance Plan for Final Inspection. The sampling plan shall be as laid down in the Quality Plan, which shall be available in the Quality Assurance Department. Lots failing to meet the acceptance criteria under the plan shall be subject to 100% inspection. Components not conforming to specification limits shall be rejected to meet the specification as the case may be. This Sampling Plan shall also be followed for inspection of material supplied by sub-contractor in process checks and final acceptance test.


Records showing application of statistical techniques, wherever defined shall be maintained by the Head of QA & Production Supervisor.


Records of Statistical Process Control shall be maintained by the Head of QA

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