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Advanced Flowchart
Flowchart is also called flow diagram or process flow map. Six sigma differentiates flowchart from process map, in which for process map, input and output must be written on the flowline. Advanced flowchart in this article means
a) the process involves more than one responsible person.
b) time, input, output may be stated on the flow lines.
c) this flowchart has three columns (denoted as column A, B, C in spreadsheet): Flowchart, Responsible and Comment. Any sequence of the columns is alright, e.g. some may prefer "Flowchart, Comment, Responsible". If desired, more columns can be added to do PFMEA (process failure mode and effect analysis).
d) the overall flow is from top to bottom.

Flowchart is the basic but yet probably the best manufacturing quality tool (probably the second best is checklist). Flowchart should be the basis on which the work is performed especially when the work team is not small. No work shall proceed if there is no flowchart or if the flowchart is not clear enough. And one may wonder how such a factory can survive without flowcharts.

Some benefits of flowchart:
1) The problem in manufacturing (e.g. illogical operation, communication breakage, useless duplication) can be surfaced when producing a flowchart. So actually the current process is not just mapped, but also fine-tuned.
2) It can be used to train up new staffs faster.
3) It creates a process-oriented environment.
4) It can be used as documented procedure for ISO 9001.
5) Sentences cannot describe manufacturing like a flowchart can. One page of flowchart is able to equal with at least two pages of written procedure.
6) It can be a basis to set job description or department responsibility.
7) Scribbling a flowchart can help in making decision.
8) It can be used to benchmark with other factory.
9) It helps in time management.
10) It is a map that prevents the team from losing direction.

Getting process information for flowchart construction

Interview related personnel before and during drawing a flowchart. The interview during drawing a flowchart is much shorter: go to that person, directly ask flowchart question, get the answer, thank theperson and go back to the flowchart. Do not show the person the flowchart yet to avoid misunderstanding that the flowchart is already finalized. Just ask question.

If there is disagreement on certain point, a meeting should be arranged. If only three persons are involved, the meeting can be an informal one in which when the person drawing the flowchart comes across Person A, he can invite Person A to go together to Person B and discuss the particular disagreed point.

Sometimes a staff may want to have the process shaped into his preference. His preference is usually rather minor or even personal. The person drawing the flowchart should be able to sense this. Such type of flow portion is neither downright correct nor incorrect. The staff should seek agreement with other staffs himself before telling the flowcharter to depict it. If an agreement cannot be reached, he should accept that the flowcharter shall make the decision.

Determine the desired output first before constructing a flowchart.

Drawing flowchart

Mindset when drawing flowchart:
a) Minimize branches. Less branches also mean less end points (less complicated).
b) Minimize bridges of communication.
c) Minimize number of sentences written in one box. One box should contain only one sentence. d) Undesired flow from a diamond shape should always go upward. Desire flow goes down.
e) Minimize number of staffs attending a meeting required in the process.

Also think of drawing it for robots. Do not expect that everyone will have common sense. Flowcharts initially were used to create logic diagram for computer to execute commands.

'Before' flowchart and an 'After' flowchart can be compared to show the improvement. First map the process and draw the flowchart as it is, then draw the flowchart as it should be.

If a step is not prerequisite for the next step to proceed, then it should run parallel instead of serial so that the process is more time efficient.

Two boxes should not be put on the same row horizontally because the responsible person for each box needs to be defined under the "Responsibility" column, unless the two boxes belong to the same person.

The length of arrow does not carry any meaning. Less major but important flow is denoted by thin arrow. Dotted arrow means flow of info.

Length of time needed to proceed to the next step can be written on each flow line. Adding the time up helps estimate the amount of time needed for that process.

At the diamond shape, usually the arrow of positive result (e.g. passed) comes out of the bottom corner of the diamond shape. The negative result (e.g. failed) arrow should come out from left or right corner. This clearly denotes that the process is not smooth (not going the main direction) when something fails.

Usually arrows do not point upward unless the flow comes out of a diamond shape (usually negative flow) or the arrow is dotted (denoting information).

For better appearance,
a) avoid having two elbows for a flow line except if it is a return line e.g. one of the flow line that comes out from from a decision option box.
b) avoid crossed / overlapped flow lines (denoted by a "jump-over" symbol in some flowcharting software). Dotted flow line can be allowed to cross other line but minimize such occurence if possible. In this type of flowchart that flows from top to bottom, usually crossed flow lines means the process is inefficient. Examples in the diagram below:
Row No. 12 in the left flowchart provides an option that the mounting checking is not done. The consequence is more steps have to be done later. When that option is eliminated, i.e. the mounting checking is done all the time, then the flowchart becomes simpler, as shown on the right.

Before
complex
After
simple

The decision option boxes (e.g. Yes and No) for diamond shape should be near to the root of the arrow. By doing so, readers do not have to look all the way along the line to know what option the line denotes.

As the flow is from top to bottom, there is no problem identifying the start point and the end point as input and output. If desired, terminator shape (horizontally elongated circle or oblong terminator) can be used.

It is good to put a full stop mark at the end of sentence in the flowchart boxes. In spreadsheet the last portion of sentence may be hidden due to change of view zoom, size of font or size of box. By having a full stop mark, the completeness of the sentence can be determined immediately.

If a process has no side branch, resembling a train, it does not need to be drawn into flowchart. It is sufficient to write the process in step-by-step point numbering. If this process is drawn into flowchart, all boxes are just on the main flow line.

If a document without a document number to refer to is mentioned in the process, it may be embedded beside the process box for user to click on it for reference. For standard hardcopy document with document number, a document shape process box document is used for quick identification.

Spreadsheet tips for flowchart

No special software is needed, just use spreadsheet (e.g. Excel) to create flowchart.

To insert a file into the spreadsheet for reference, go to Insert > Object... > Create from File.

To expand some space to add more step, select the rows by clicking on the row number, right-click and choose Insert.
insert row

The row height in the spreadsheet should be all the same. The default is 12.75 for font size 10.

To copy a box or line, select it with mouse pointer, hold down 'Ctrl' and move the mouse pointer.

To move the box vertically or horizontally according to mouse pointer speed, hold down 'Shift'.

To move multiple boxes without messing up the alignment, click 'Select Objects' select objects and drag a box to include all of them and move.

To fit the flowchart to full pages when printing to avoid waste of paper, adjust the scaling and see the adjustment outcome in print preview:
scaling

"Snap to Grid to grid" is not suitable to be used because it requires all cells to be in identical size.

Others

It is acceptable to have one flowchart for each small process. For example the process to repair a warranty part and the process to replace a warranty part can be two flowcharts.

The method to measure the performance of the process to achieve the desired output can be addressed too.

Take note that the ownership of processes (illustrated by flowcharts) does not belong to quality assurance (QA) department although often QA has the bird's-eye view of processes. QA can draw flowchart. Each process is owned by the related department manager(s). Managers should be sensitive towards the content of the flowcharts. Any doubt in mind for the flowchart should not be ignored. When there is any argument, refer to the flowchart. If the flowchart is not precise enough, get QA to improve it. Ultimate decision of how the flowchart will look like shall be made by process owner and QA. The big boss may give suggestion.

Do not expect a flowchart can be completed on the first attempt. Disagreement among staffs is very common. The person drawing the flowchart should be able to solve the disagreement. Also new things can pop up in mind for example exceptional situation that needs to be specially addressed in the flowchart.

After a flowchart is completed, it should be communicated in the meeting formally to the persons who are in the process of the flowchart. After the meeting it should be assigned with a document number, revision number, a start date, a record of signing off by the process owner(s) and a place where the staffs will regard all the law and constitution are. Of course a test run for a period can be arranged before it is formalized. After assigning a revision number, for any change that informally cannot move the people to work according to the change, change the revision number.

For the flowchart to be followed, of course it must be agreed by all related department leaders. Any flowchart displayed publicly is deemed to be already being followed by the process owner.

Whenever there is option for checking something (often denoted by a diamond shape diamond), there should be some data output on the failure rate at that point.

In daily work, if something cannot be fulfilled at a particular flowchart step, stop at that step. Always loop back the error to the previous step. Wait until everything is corrected before proceeding to the next step. If the process always stops (or even going backward due to the activity of looping back the error) at a particular step, then there is a bottleneck to improve. A KPI (key performance indicator) should be measured at this bottleneck, e.g. process stopping rate. Example of such situation is when the order processing department receives unclear order from sales department, the order processing department must not proceed to process the order but to return the unclear order to sales department. The percentage of this type of return should be measured.

When reference to a particular box in the flowchart has to be made (such as in an audit), just utilize row number on the left in the spreadsheet window. The row number for a box will not change unless there is addition / deletion of boxes before that particular box. Modified flowchart should have a new revision number.

Process performance may still be affected by staff's attribute even there is a perfect flowchart. If a staff is found to be more careless than others, then human resource should be looked at instead of the flowchart.

There is an ISO standard for flowchart: ISO 5807.

Download: 1) flowchart_example.xls 2) flowchart_template.xls
Posted: 2008-04-10; updated: 2014-01-06 by Ong Seng Aun.
I categorize this article under Manufacturing. Other articles are accessible from home page.
External pages that link to this article:
  1. Man On The Moon
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