Quality Assurance + Process control Flashcards
Define “quality”
Conformance to requirements and specifications (overall characteristics of food that determine its value and acceptability to consumers)
Name some standards (ie colour)
-Purity
-Strength
-Flavour
- Size
What are the four standards of quality?
1- Legal
2 - Industry
3 - Company
4 - Consumer
Define Legal standards
- Made by federal, state or municipal agencies
What do legal standards aim to achieve?
1 - Freedom from adulteration
2 - Safety (antibiotics, moulds, pesticides, addatives)
Define industry standards.
An organized group established limits of quality (standard of identity)+ ensure consistency
What are some things that are examples of industrial standards.
- standards in order to** identify** (ie. ice cream contains not less that 10% milkfat etc) -> product definitions
-standards of food safety
-Nutritional standards
-Packaging andlabeling standards
-labour standards
What are the three tools for quality assurance:
Statistics, sampling, control charts
What are the two forms of process control using data?
- Supervisory Control And Data Acquisition (SCADA)
- Statistical Process Control (SPC)
What is SCADA used for?
Automation systems - collects data from sensor etc. and analysis + control
What is SPC?
- A** quality control technique** where a process variable or quality attribute is** measured and tracked over time.**
- Management technique for monitoring and controlling a process.
What data is collected during SCADA and SPC?
Some property of the system or product is measured (ie. temp, pressure, speed, pH etc)
What is the purpose of using SCADA and SPC?
to determine if the process needs adjusting to maximize quality and minimize defects.
What is a set point in SCADA (SP)
Desired value for the process
What is the Process Variable (PV) in SCADA?
**Actual measured value **from the process
What is an error defined as?
The difference between the Process Variable and Set Point (PV-SP)
What is the control output (CO)?
a Mathematical function of the process error used to control the equipment.
What is Human Machine Interface (HMI)?
Connection to the operator (display, touchpad, keyboard, buttons, indicator lights, gauges etc)
What is used to preform SPC?
- SCADA system process variables (flow rate, tempt, pH etc)
- From quality assurance ;ab measurements of product samples taken off the line.
How does SPC see if the process is in control?
Analyze measured data from QA lab and SCADA
What determines whether the process is in control during SPC?
1 -** Location**: determining whether the system is delivering the product within specifications (is the value between limits?)
2 - Variation: determine whether the manufacturing process is stable and consistent
What are the two types of process variation?
1 - Common Cause Variation
2 - Special Cause Variation
What is Common Cause Variation?
Natural background variation (normally a bell curve)
- due to the effect of cumulative small, random and uncontrollable factors.
- part of any stable process.
What is Special Cause Variation?
Variation that is not present in the system at all times (patterns, drifting, cycles and increased variation, outliers)
Define Type I error
Ascribed variation to a special cause when it really was a common cause
Define Type II error
Ascribed variation to a common cause when it really was a special cause.
What reduces the probability of a Type I error?
A 3 derivative confidence limit
What are the purposes of a control chart?
1 - Get a picture of the process over time
2 - Understand + predict process capabilities
3 - Easily identify process shifts
What is the purpose of the centre line in a control chart?
It is considered the target value of the process.
What is the grand Average in SPC?
The average of the subgroup averages
What is the average standard deviation for SPC
The average of the subgroup standard deviations
What are company standards?
Voluntary standards
What are consumer standards?
Consumer requirements
