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Graphic Products Systems and Control


Learning objectivesL

earn

ing

ob

ject

ives


inputs, processes and outputs

systems in graphics equipment

flow charts

Gantt charts

scales of production

simple mechanisms.

To learn about:


We are surrounded by systems in our everyday lives – they are used in all sorts of tasks, from turning on a light, to manufacturing the latest kettle. Every system is broken down into three key areas:

Input, process and output

These are the outcomes – the end results of the system.

Outputs

These are the activities that transform the inputs into new forms – for example, painting, cutting and laminating.

Processes

These are the things that are put into the system – the physical materials, energy and labour supplied.

Inputs


There are two types of systems: ‘open loop systems’ and ‘closed loop systems’.


Closed loop systemsThese are systems that involve feedback. The

output is monitored, and the information fed back into the system to improve the next outcome.

Open loop systemsThese are usually simple linear processes, e.g. turning on a light. The input leads to a process, which creates the output.

InputPress the switch

ProcessEnergy flows through the wire

OutputLight

comes on


Your central heating system is a good example of a closed loop system.

InputYou set your

thermostat to the temperature you want the room.

OutputThe radiators warm up the room to the

required temperature.

ProcessThe boiler turns on and heats up the water for the

radiators.

FeedbackThe thermostat senses the temperature. If the optimum temperature is reached, it

turns the heating off.When it gets too cold it turns

the heating back on.



Systems using feedback


The principles of a system can be applied to all graphics equipment. Here is the system for using a paper trimmer:

Most tasks can be broken down into inputs, processes and outputs – you just need to be aware of how each task is performed.

Systems and control

InputThe user applies physical force to slide the rotary

blade across the trimmer.

OutputPaper that has been cut in a neat, straight

line.

ProcessThe rotary

blade cuts the paper.


See if you can work out the systems for the following pieces of graphical equipment (use the next slide to help you).

Don’t forget to include any feedback involved.

Think about what it is about each system that ensures

‘accurate, repetitive operations that produce identical products and outcomes’?

Computer plotter

Systems and control

Printer

Digital camera


Systems and control


It is possible to present the step-by-step process by which something is made using simple diagrams.

The different stages of production can be grouped together into key areas of manufacture.

When planning a production line, different operations can be coded using different symbols:

TerminatorRepresents start

and stop (and restart, if needed).

Input/OutputRepresents items added or removed from the system.

ProcessRepresents an action or task.

DecisionRepresents a

choice that affects the next stage of

the process.

Flow charts


The symbols are arranged to show the order in which tasks are carried out, and are then linked together using arrows.

Some flow diagrams are drawn vertically, others flow around the page – it depends on the space available. Here is an example:

Start

Adjust the heat

Are the beans cooked?

Open can of beans

FinishPour beansinto a bowl

Turn off heat

Heat

Pour beans into the saucepan

NoYes

Flow charts

Can of beans


Flow charts


When you are working on a project, you need to plan your time carefully. This can be done easily using a Gantt chart.

Stage

Weeks

1 2 3 4 5 6 7 8 9 10

Research into CD cases

Produce 6 initial ideas

Develop a final design

Presentation drawing

Gantt charts

A Gantt chart shows all the processes that go into a making a product. You fill in a number of blocks to show how long each task takes – some tasks may overlap if they can be done at the same time.

The chart shows how long it will take to make the end product.


Gantt charts


It is important that you think about how you will manufacture your designs.

Scale of production

When you are only making one product by hand, it is easy to answer these questions, but there is much more to think about when you are considering large scale manufacturing.

How many would you make?

How would you manufacture that number?

How would you ensure quality?

Within school, you will usually only manufacture one copy of your product. However, you must think about what would happen if that product went into large scale production.


When planning your manufacturing, it can be useful to break the process up into smaller, more manageable chunks.

Manufacturing plans

It is crucial that you include predicted timings in with any manufacturing plan, whether it is one-off or large-scale.

You could break up the stages and put them into a detailed Gantt chart. This will give you a clear overview of how long the production is going to take and help you to decide the best order in which to do things.

You can write a step-by-step plan, including imagery to help you. This will produce a clear explanation of your manufacturing process.

You can write them as a list of bullet points, so each stage is clear.


There are 4 types of motion:

Mechanisms – motion

Linear

Rotary

Reciprocating

Oscillating

Graphic products are not always static, 2D objects. You can also make models which involve some movement.

A good example of a dynamic graphic product is a pop-up book.


Linear motion is the most basic of all the motions. If an object is moving in linear motion, it is travelling in a straight line.

A good example of a object that displays linear motion is a train.

Linear motion


Rotary motion moves in circles.

Rotary motion is fairly common and can be found in a number of objects…

Rotary motion

…for example, in a wheel.


Reciprocating motion is the motion of an object when it moves backwards and forwards.

An example of reciprocating motion is the action a person’s hand would make when using a hand bike pump.

Reciprocating motion


Pendulums and metronomes move in an oscillating motion.

Oscillating motion

Oscillating motion is a cross between rotary motion and reciprocating motion. It involves backwards and forwards motion, but in an arc rather than a straight line.


Mechanisms

What kinds of mechanisms are there in this picture?


Mechanisms can convert motion from one type to another. Look through the mechanisms on the following slides, and then see if you can spot which motions are being converted, and into what.

rack and pinion

levers

linkages

gears

cranks

cams

pulleys.

Some of the mechanisms we are going to look at are:

Mechanisms


Rack and pinion

The rack is a flat, toothed area and the pinion is similar to a gear wheel.

The rack and pinion convert rotary motion to linear motion (or vice versa).

Gears Gears are discs with toothed edges which rotate around a central axle. They come in a variety of sizes and are used to change the direction and speed of motion. However, the motion always remains rotary in nature.

A worm gear can change the rotary motion by 90°, as well as affecting the speed.

Mechanisms


Levers Levers are an essential part of many mechanisms. They can be used to change the strength and direction of movement.

Levers magnify the strength of forces. The longer the lever, the more the force is magnified.

The fixed point of a lever is known as the fulcrum.

Two common examples of everyday levers are a pair of scissors and a seesaw.

Mechanisms


LinkagesLinkages allow the direction of motion to be changed.

This linkage converts vertical reciprocating motion into horizontal reciprocating motion.

Cranks Cranks convert rotary motion to reciprocating or oscillating motion.

As the wheel turns, the crank moves from side to side in an oscillating motion.

Mechanisms

Pivot


Cams

Cams are used to convert rotary motion into reciprocating motion.

The motion that is created can be simple and regular…

…or complex and irregular.

The cam follower follows the profile of the cam.

The cam must be well designed to produce the motion required.

Mechanisms

cam

cam follower


Pulleys Pulleys are used to transfer motion. They work under rotary motion. Motion is passed along a pulley belt causing more pulleys to turn.

The sizes of the pulley wheels determine the speed of motion – this can be altered accordingly.

Mechanisms

You can twist the belt, causing the rotary motion to change direction.

Pulleys can also increase the strength of a force, and are useful for lifting heavy objects.


Mechanisms


Key pointsK

ey p

oin

ts


Systems consist of inputs, processes and outputs.

Systems can be represented simply using flow charts.

Gantt charts can be used to design efficient production processes and help you to estimate how long production will take.

Scale of production must be considered when planning your manufacturing system.

There are four basic types of motion – linear, rotary, reciprocating and oscillating.

Motion can be converted from one form to another using simple mechanisms.

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