NIRMAL THOMASM.TECH ROBOTICSSRM ROBOTICSBATCH : 2013-2015

ROBOT CYCLE TIME ANALYSIS

TIME ………………..Every Seconds Count

“TIME IS MONEY.” – BENJAMIN FRANKLIN

1. This is true when applied to industrial manufacturing. The longer a system takes to get back online, the more money a company loses.

2. Think about it. When you are not producing, you are not making money. The longer manufacturing and maintenance takes, the more money you lose. It is an ugly fact.

3. However, the faster the tool the faster the job is completed and the faster you get back to producing.

4. For manufacturing within the specified time you need to operate faster, product should be perfect and complete in all sense

• CYCLE TIME ANALYSIS :The period required to complete one cycle of an operation; or to complete a function, job, or task from start to fi nish. Cycle time is used in diff erentiating total duration of a process from its run time.

A cycle time analysis is any method that collects and analyzes time data for a process to improve the total process or system.

Benefits of CTA

1. Easy to use

2. Identifies time required to complete specified tasks

3. Allows for easy identification of process improvements and efficiencies

How to Use CTA

Step 1. Identify the process and detail the scope to be studied. Step 2. Map the process. (Process Chart)Step 3. Take several time measurements at varying points. Step 4. Study the process between measuring points to determine if there is wasted time. Step 5. Analyze the data. Step 6. Make changes as needed.

Robot Cycle Time Analysis… Cycle time determines the robot production rate for the job, which is a significant factor in the economics service Installation.

1. MTM (Methods of the Measurements)

2. RTM (Robot Time and motion) by Nof and Lechtman at Purdue University.

In this each action of the robot is expressed as different elements so that we can easily calculate the time of each action.

RTM Elements

These 10 elements can be categorized into four major group

1. Motion Element : These are manipulator movements performed either with or without load

2. Sensing Element : These are sensory activities performed by robot equipment's with sensing capabilities (VI & F)

3. End effector Elements : End effector action of the robot (GRi)

4. Delay Elements : These are delay time resulting from waiting and processing conditions in the work cycle (T & D)

4 Major Approach In RTM 4 major approaches are used to determine the element time and analyze a robot cycle with RTM

1. Table of Elements :- Just recording the time taken for each action from clock. In this time values are determined for the different elements listed in the table

2. Regression Equation :- In this regression equations are formed for the complicated elements whose values are functionally related to several factors. Once the equation is developed for the given elements , the user simply puts the values into the equation to calculate the time.

3. Motion Control :- Motion control is concerned with the kinematics and dynamics analysis of the manipulator movements. It determines the element time values by considering the distance moved and velocity to make the move.

4. Path Geometry :- This approach is similar to motion control and requires specification of the motion path to be followed together with robot joint and arm velocities.

Problem

The work cycle consist of simple task in which the robot must move parts weighing 3lb from one conveyor to another conveyor. The conveyor delivers a part to a fixed position every 15 seconds

Sequence

1. Robot pick up part from first conveyor.

2. Robot transfer the part to second conveyor and release the part.

3. Robot moves back to ready position at first conveyor.

Conveyor 2

Conveyor

1

Robot

Start position

Pick Up point

Drop Position

15 inch

(1.25 ft)

1.2 inch (0.12 ft)

1 Feet = 12 inch

Work piece 3lb

Process Flow Chart

The flow process chart in industrial engineering is a graphical and symbolic representation of the processing activities performed on the work piece.

When to use it ?

1. It is used when observing a physical process, to record actions as they happen and thus get an accurate description of the process.

2. It is used when analyzing the steps in a process, to help identify and eliminate waste.

3. It is used when the process is mostly sequential, containing few decisions.

Symbols in Process Chart