Key Stages of Production
Four different methods of showing the Stages of Production are described, going from the simplest to a computer run system that can control huge projects.
Sequence Of Operations
Critical Path Scheduling
All materials must be fully inspected as it make no economical sense to make faulty goods from the start.
Some companies even put their own Inspectors into their Suppliers factories to stop any faulty materials or components being delivered. They have to pay for this anyway and it puts pressure on their Suppliers to make quality products.
All manufacturing stages can be broken down into a “Sequence of Operations” separating processes into logical/practical units of work.
It is the Inspectors role to look at this Sequence of Operations and decide where to insert “Critical Control Points” into the manufacturing process.
This is the final stage before the products or services are delivered to the Wholesaler or Customer. The quality of the packaging process needs to be checked. Are all the leaflets correctly inserted? Does the outer carton have the correct labelling/bar code?
Companies should inspect their complete delivery system from their own warehouse to the customer. Nothing is worse than spending all that money to make high quality products only to have them damaged in transit.
Sequence of Operations.
This is a simple way to show the Stages of Production. It does have the advantage of listing all the equipment to be used.
|2||CCP 1 Raw Materials||Visual, Rule.|
|3||Cut to Length||Power Hacksaw. Rule.|
|4||Deburr Ends||Grinding Wheel.|
|5||Round Corners||Grinding Wheel.|
|6||CCP 2 Cut Strip||Visual, Rule.|
|7||Drill 1st Hole||Drilling Jig, Pillar Drill.|
|8||Deburr Hole||Countersink Bit, Bench Drill.|
|9||Drill 2nd Hole||Drilling Jig, Pillar Drill.|
|10||Deburr Hole||Countersink Bit, Bench Drill.|
|11||CCP 3 Holes||Dowel Pins, GO/NO GO Gauge.|
The flowchart shows the Key Stages of Production with the Critical Control Points and Quality Indicators. It could be extended to show Distribution and Customer Service.
The flow lines show how defects are corrected and how Scrap is dealt with.
Gantt charts show how long each Stage of Production takes. The operation time is shown by the length of the bar. The diferent types of operations (production, inspection, set-up) can be shown by colour coding the bars. Verticle lines help to show the time scale.
This method of showing the “Stages of Production” is very useful as you can see at a glance which stages are causing time delays and how they can be altered to reduce the overall time and eliminate bottlenecks.
Click picture to enlarge.
Critical Path Schedule
This is a form of Flow/Gantt Chart. It shows a logical progression of work and includes time. It is easy to run on a computer.
Instead of one job following another, it is possible to show jobs running at the same time. If they have to finish at the same time the lines go to the same Node. The dotted lines are dummy logic links, saying one job cannot start before another finishes.
To give each operation a unique identifier, you combine the start/finish Node numbers together. 0508 Cut to Length 5 hours.
Click picture to enlarge.