Page 133 - DMGT552_VISUAL_MERCHANDISING

Visual Merchandising

Notes and side clamping. It is usually used to restrict a workpiece’s movement to keep it stable
during processing .The clamping planning determines clamping surfaces and points on
the workpiece and clamping components, the magnitude of each clamping force, and the
clamping sequence when the stability of the workpiece becomes a concern. Some locating
and clamping variations may be applied for different part geometrical and processing
requirements. Fixture assembly planning determines the fixture assembly sequence and
assembly tools used. It can also verify the possible interference of fixture components and
workpieces in an assembly process, and the ease of workpieces loading and unloading.
The fixture planning requires workpieces and machining information including geometry,
material, dimension and tolerance, processing plan and tool path. To hold a specific part, several
design constraints may be applied. Among them, four main constraints in the fixture planning
are as follows:
1. Geometrical constraints: Accurate locating of a workpiece should be ensured to meet
machining accuracy requirements of a workpiece.
2. Accessibility constraints: There should be no interference among fixture components,
workpieces, and machining tools during assembly and machining. In addition, it should
be easy to load and unload the workpiece.
3. Force constraints: The fixture should be strong enough to resist the forces and moments
produced by clamps and machining tools. A minimum clamp force should be specified for
the workpiece stability.
4. Deformation constraints: The stiffness of a fixture system should be sufficient to keep the
workpiece deformation within the design tolerance.
CAFP can be divided into four phases: problem description, fixture analysis, fixture synthesis,
and fixture verification. The problem description defines fixture design variables, design
constraints and design objectives. In the fixture analysis, a workpiece-fixture interaction model
is built in terms of geometry, kinematics, force and deformation. The analysis result is then used
to select the locating, supporting and clamping surfaces and points on the workpiece. The fixture
synthesis determines details of the fixture configuration including selecting fixture elements,
placing the elements in suitable locations, and generating fixture assembly plan. The fixture
configuration is verified in respect to geometrical interference, locating determinant, clamp
stability and machining tolerance in the fixture verification phase. If design objectives are not
satisfied, the result will be sent back to fixture analysis phase for further improvements.

Self Assessment

Fill in the blanks:
11. Fixturing is generally concerned with the .......................... of merchandise in what is
sometimes termed ‘on-shelf’ displays and is the routine display of goods from which
customers are expected to make their selection.
12. An array of different types of fixturing may provide .........................., but it can make a store
appear cluttered and untidy.
13. Fixture planning is a complex activity restricted by the .......................... of workpieces and
several environmental factors including machine tools, assembly tools, grasping devices,
and cutting tools.
14. .......................... can be divided into four phases: problem description, fixture analysis,
fixture synthesis, and fixture verification.
15. A .......................... clamp force should be specified for the workpiece stability.

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