PLTW CIM Final Review

Jig

A device that holds and locates a piece of work and guides the tools that operate upon it. Example: table, anything that is used to guide material.

Fixture

A device designed and built for holding a particular piece of work for machining operations without the ability to guide tools

Postprocessor

A post-processor is in essence software and or a sequence of instructions to deal with a nuetral format generated by a CAM system and translates that nuetral language to one that makes your CNC control happy.

Flexible Manufacturing system

Adapts efficiently to changing need, allows the system to react in case of changes whether predicted or unpredicted.

Lean manufacturing

Systematic elimination of waste. Entire system must participate to produce effectively

six sigma

indicates measure of quality for near perfection. Produces fewer than 3.4 defects per million opportunities. Identifies and corrects causes of defects. Utilizes the five "whys" to uncover root cause.

kaizen

japanese for improvement. Based on continuous improvement by everyone.

mass production

the production of large amounts of standardized products whereas handmade production makes a smaller number of items

work envelope

range of motion of a robot or machine

rapid prototyping

prototype made directly from a computer model. several technologies: sterolithography, 3D printing, selective laser sintering, fused deposition modeling.

work cells

an arrangement of resources in a manufacturing enviroment to improve the quality speed and cost of the process

tolerance

an allowable amount of variation of a specified quantity, especially in the dimensions of a machine or part

repeatability

indicates how close together repeated measurements of the same quantity are to each other.

accuracy

indicates how close measurements are to the actual quantity being measured.

closed loop

a type of control system that automatically changes the output based on the difference between the feedback signal to the input signal. Requires feedback from sensor input to control outputs.

open loop

a type of control system that uses only an input signal to actuate an output. there is no automatic feedback to adjust the process so adjustments must be made manually by the operator. Example: you tell the motor to turn on for a specified time, not controled by sensors.

limit switch

can be used to Home a robot by indicating that the machine has reached the max extent of its travel along an axis.

additive process

fabrication of a part by adding material. 3d printing

subtractive process

Processes that remove material to change the size, shape, or surface of a part. There are two groups of separating processes: machining and shearing.

fixed cost

A periodic manufacturing cost that remains (more or less) unchanged irrespective of the output level or sales revenue of a firm. Such costs include rent, phone service, internet, lighting

variable cost

Periodic manufacturing cost that varies, more or less, in step with the output or the sales revenue of a firm. Such costs include raw material, energy usage, labor (wages), distribution costs, etc.

profit

The monetary surplus left to a producer or employer after deducting wages, rent, cost of raw materials, etc.

overhead

The general, fixed cost of running a business, such as rent, lighting, and heating expenses, which cannot be charged or attributed to a specific product or part of the work operation.

raw materials

Basic substance in its natural, modified, or semi-processed state, used as an input to a production process for subsequent modification or transformation into a finished good.

primary processing

The first step in manufacturing where raw materials are processed into a usable form for further manufacture.

tolerance

The amount of interference required for two or more parts that are in contact. The amount of variation, over or under the required size, permitted on a piece of machined work.

absolute

System in which positions are given with respect to a fixed point, usually the origin.

Incremental

A system in which each position is taken from the one prior. Also called relative.

end effector

A tool or gripper attached to the end of a robotic arm.

control system

A system in which one or more outputs are forced to change in a desired manner as time progresses.

handshaking

Handshaking is a form of communication where a signal is sent from a device to another similar or dissimilar device(s).

pneumatics

The use of a gas flowing under pressure to transmit power from one location to another. Gas in a pneumatic system behaves like a spring since it is compressible - quicker, jumpier motion, not as precise.

hydraulics

The use of a liquid flowing under pressure to transmit power from one location to another. Liquid in a hydraulic system behaves like a solid since it compresses very little - slower, smoother motion, more precise.

injection molding

- A process during which plastic is heated in a machine and forced into a cavity by a screw or ram. The material solidifies and is then ejected.

payload

The maximum weight that can be carried by a robot in normal and continuous operation.

absolute encoder

An encoder whose count remains absolute despite potential power disconnections.

incremental encoder

A device providing a series of periodic signals due to mechanical motion. The number of successive cycles (signals) corresponds to the resolvable mechanical increments of motion (measuring steps).

decision matrix

A tool for systematically ranking alternatives according to a set of criteria.