View
217
Download
0
Category
Preview:
Citation preview
7/28/2019 designing_for_marking.pdf
1/18
77. DESIGNING FOR MARKING
77.1. REASONS FOR MARKING
The widespread practice of marking products, parts, and materials has many
purposes. They include the following:
1.For production identification. Product and brand names and model names
and numbers are normally included on finished products.
2.For advertising. Trademarks, the manufacturer's name, and model
identification all have advertising value if attractively presented.
3.To indicate grade, size, or class of a material or component.
4.To indicate that an inspection or other manufacturing operation has
been carried out.
5.To indicate the part number in case product repair is later required.
6. For patent protection.
7.To indicate the date of manufacture or the product's serial number.
8.For decoration.
9.To indicate dimensions of components before selective assembly.
10.To provide graduations or other functional marks.
11.To provide instructions on the operation of the product.
12.To display product specifications such as horsepower, voltage, etc.
13.To provide automatic data collection through the use of bar codes or
other readable markings.
77.2. MARKING METHODS
DESIGNING FOR MARKING
http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001?UserEmailParamInPdfDownloadController=rameshsmit@gmail.com#p13n-login-panelhttp://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001?UserEmailParamInPdfDownloadController=rameshsmit@gmail.com#p13n-login-panelhttp://accessengineeringlibrary.com/7/28/2019 designing_for_marking.pdf
2/18
The designer has a wide range of marking methods to choose from. They
include the following.
77.2.1. Freehand Marking
This is a fundamental method of applying visible markings to many kinds of
surfaces, using brush, crayon, chalk, pencil, pen, or a similar hand-impelled
marking device. The marking action always involves the transfer of part of
the marking medium (e.g., ink, stain, paint, pencil graphite, etc.) to the
marked surface.
77.2.2. Printing
Printing, either directly to a workpiece or to a nameplate, label, or tag, is a
common marking method. In industrial marking, it most frequently involves
transferring an image from an inked printing die, usually rubber, onto the
surface being marked. This is calledlexographicor contact printing.
Noncontact printing uses paint or ink applied by means of a spray. This is
commonly referred to as ink-jet marking.
77.2.3. Stenciling
When ink, paint, dye, stain, or other fluid coloring is applied to any surface
through the openings of a marking device so that the shape of the aperture
controls the form of the mark, the method of application is known as
stenciling. The fluid coloring may be applied by brush, spray, roller, or a
similar implement, and the stencil may be prepared from paper, steel, copper,
rubber, plastic, etc. Also, abrasives can be sprayed through a rubber or
plastic stencil to mark materials such as marble, glass, and ceramics.
Silkscreen printing (described in Chap. 6.12) is another stencil method
particularly useful when decorative effects or attractive brand or model
names are marked on a finished product.
77.2.4. Etching and Engraving
These two kinds of marking produce marks on the surface of metal or other
material by removal of part of the material in such manner that the material
remaining forms the desired marking. In the case ofengraving, the material
removed is cut away by sharp or abrasive instruments; in etching, the
http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109976_195001#p2000af109976_1950017/28/2019 designing_for_marking.pdf
3/18
7/28/2019 designing_for_marking.pdf
4/18
for in this process the workpiece to be marked is struck or pressed against
the dies with such force that the metal or other material flows into conformity
with the dies shape.
Embossing is commonly used for marking metal tags. Individual tags or tags
in continuous coils may be embossed by manually activated or automatic
embossing machines.
77.2.9. Stamping
In this common method of marking, the lettering or other symbols are
impressed into the surface of the workpiece. A hardened die is forced into
the workpiece surface either by a steady press force or by impact. The latter
may be applied manually by a hammer blow, one letter or symbol at a time.Pneumatic, hydraulic, mechanical, or solenoid presses can stamp
combinations of characters in one stroke. Roll-marking devices are also
economical for many applications.
Programmable stampers that generate characters or graphics by indenting
multiple dots or impressions to form a recognizable shape are widely used.
Flexible software enables the stamper to imprint numbers, diagrams, or logos
on a wide variety of substrate materials.
77.2.10. Nameplates, Labels, and Tags
These are often used to provide the same kind of information that would
otherwise be marked directly on the product. All the marking methods noted
above are also applicable to nameplates, labels, and tags, provided the base
material is suitable. A variety of fastening methods are available fornameplates, but threaded fasteners, adhesives, and rivets are used most
commonly.
7/28/2019 designing_for_marking.pdf
5/18
Figure 8.6.1. Common methods for product marking. (a) Offset print
marking metal bar stock with rubber type. (Courtesy Pannier
Corporation.)
77.2.11. Decals
The transfer of printed material from plastic film or paper to the product's
surface provides a means for displaying brand names, trademarks, and
decorative material in an attractive manner.
77.2.12. Machine-Readable Identification
This includes markings of several types that can be read by computer-
connected optical scanners and high-resolution video devices. Bar codes or
characters designed specifically to be machine-readable can be used.
Radio-frequency identification (RFID) encompasses a wide range of
applications, notably railroad cars and highway toll plazas where informationcan be read at high vehicular speeds, despite fog, mist, dust, grease, oil,
snow, ice, darkness, walls, and other obstacles. RFID requires separate
tags that are applied to products by various methods.
7/28/2019 designing_for_marking.pdf
6/18
Figure 8.6.1 illustrates a number of these marking methods.
77.3. CHARACTERISTICS AND APPLICATIONS
Table 8.6.1 lists some dimensional characteristics and applications of the
common kinds of markings.
77.4. ECONOMICS
Table 8.6.2 summarizes the economic factors attendant on the common
marking methods.
77.5. SUITABLE MATERIALS
Table 8.6.3 summarizes commonly used or advantageous materials for each
listed marking method.
77.6. DESIGN RECOMMENDATIONS
Perhaps the most important question facing the design engineer with respect
to marking is its location on the product. Several considerations are
applicable:
http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_111001http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_109001http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_108001http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_1020017/28/2019 designing_for_marking.pdf
7/18
Figure 8.6.1. (Continued) Common methods for product marking. (b)
Embossing; material remains essentially uniform in thickness. (c)
Coining; material flows into die depressions.
1. The marking location should be accessible to the marking device.
Overhangs and deep and narrow recesses should be avoided.
2. The marking should be visible. Brand identification and trademarks must
be prominent; nameplates and other identifying material should not be
located in an obscure position.
3. When the final marked component or product is bulky, it is usually more
convenient and economical to mark an individual part before assembly.
Other considerations are the following:
1. The surface to be marked should be flat. Cylindrical surfaces are also
satisfactory for stamp indenting and some other methods, but spherical or
irregular surfaces always present a problem. Hand-finished surfaces may be
difficult because of poor flatness.
7/28/2019 designing_for_marking.pdf
8/18
Figure 8.6.1. (Continued) Common methods for product marking. (d)
Apparatus for noncontact ink-jet marking of components and
cartons. (Courtesy Pannier Corporation.)
2. When it is desirable to mark without displacing the metal of the workpiece,
the following methods can be employed: acid etching, grit blasting with
stencils, silk screening, and stencil and other printing methods.
3. Surfaces to be used for freehand or stenciled lettering should not be too
small.
4. Decorative designsetched, silk-screened, printed, embossed, or
otherwise applied to an open surfacecan serve to hide surface
imperfections such as nicks, scratches, etc.
5. When two or more areas of different color are incorporated in a silk-
screened, lithographed, or stenciled marking, the designer should allow for
possible mismatch of the colors. If one color is not completely opaque when
overprinting another, a dividing line of 1.2 mm (3/64 in) should be allowed
between the two areas if silk screening is used and 0.8 mm (1/32 in) if
lithography is used. (See Fig. 8.6.2.)
The following design recommendations apply to embossed markings:
1. To avoid an oilcan effect and to simplify tooling, limit the depth of
embossed lettering to one material thickness. The stroke (letter leg width)
http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_1120027/28/2019 designing_for_marking.pdf
9/18
should be at least three times the material thickness. Figure 8.6.3 illustrates
these rules.
2. The angle of bevel of embossed lettering, as also illustrated in Fig. 8.6.3,
should normally be between 35 and 40. For sharpness and clarity of
lettering, the angle
Figure 8.6.1. (Continued) Common methods for product marking. (e)
Marking a casting with programmable stamper that generates a
series of depressed dots. (Courtesy Pannier Corporation.)
http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_112001http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_1120017/28/2019 designing_for_marking.pdf
10/18
Figure 8.6.1. (Continued) Common methods for product marking. (f)
Methods of stamp-indenting cylincrical parts.
can be held within 25 to 30, but the wider angle provides easier metal flow
and longer die life.
The following design recommendations apply to stamp-indented markings:
1. A number of character styles and faces are available in standard
commercial stamping dies. Figure 8.6.4 illustrates popular lettering styles.
Sharp-faced gothic characters are recommended for best clarity of
impression and easiest operation.
2. Round-faced and interrupted-dot marking dies are advisable if there is a
need to minimize induced stresses in the workpiece. (See Fig. 8.6.5.)
3. Generally speaking, the smallest lettering commensurate with good
legibility should be specified even when ample marking surface is available.
Small characters require less force and more easily produce a clear, well-
defined impression.
4. A series of high-legibility numbering dies has been developed by the Steel
Marking Tool Institute for hand stamping in situations in which part of any
character may not be distinct. This type of numbering is recommended for
miscellaneous handstamping applications. (See Fig. 8.6.6.)
77.7. RECOMMENDED TOLERANCES
Table 8.6.4 presents recommended tolerances for various marking elements
including nameplates. The values shown are for normal, noncritical
applications. When necessary, closer tolerances than those shown can beheld for product appearance or other reasons. If so, however, tooling and
processing costs usually will be increased.
http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_114001http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_113002http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_113001http://accessengineeringlibrary.com/browse/design-for-manufacturability-handbook-second-edition/p2000af109978_99001#p2000af109968_1120037/28/2019 designing_for_marking.pdf
11/18
Table 8.6.1. Characteristics and Applications of Markings Made by
Various Methods
Marking
method
Minimum
recommended
letter height,
mm (in)
Permanent
or easily
removable
Remarks
Typical
applicatio
Freehand 2.5 (0.100) R Appearance
and legibility
poor; limited
information
Raw-materi
grade (colo
code),
various
identificati
tags
Contact
printing
1.5 (0.060) R Multicolors
feasible
Raw-materi
grade,
identificati
labels, tags
nameplates
Noncontact
printing
1.5 (0.060) R High print
quality
Raw
material,
shipping
containers
Stencil 6 (1/4) R Good for
largersized
lettering
Shipping
cartons; wi
abrasive
blasting,
glass, and
ceramics
component
Silk screening 1.5 (0.060) R Good
appearance;
can be
detailed anddecorative
Signs,
instrument
panels, cloc
faces
Etching 1.5 (0.060) P Normal Ruler and
7/28/2019 designing_for_marking.pdf
12/18
*1.5 mm recommended for legibility; smaller lettering possible.
depth of
etch, 0.07
0.3 mm
(0.0030.012
in); much
finer work
possible with
photographic
techniques
instrument
graduation
Engraving 2.5 (3/32) P Nameplate
plaques
Cast-in,
molded-in
Sand mold, 4
(0.160) Plastic
or diecast, 1.5
(0.060)*
P May be
raised or
depressed
Automotive
engine bloc
many plasti
and die-cas
products
Branding 1.5 (0.060) P Wooden to
handles
Hot stamping 1.5 (0.60) P Decorativewith metallic
and other
colors
Smallappliances,
cosmetic
containers,
golfballs
Embossing 4.8 (3/16) P Good
appearance
and legibility
Metal
identificati
tags
Programmable
stamper
1.0 (0.04) P Good
resolution
Part markin
of work in
process
Laser marking 1.0 (0.04) P Excellent
legibility on
small parts
Electronic
component
7/28/2019 designing_for_marking.pdf
13/18
Table 8.6.2. Economic Factors for Various Marking Methods
Table 8.6.2. Economic Factors for Various Marking Methods
(Continued)
*No additional direct cost if impression tooling is incorporated in a normal punch-press or
screw machine operation; otherwise moderate.
Equipment cost may be high but can be amortized over large quantities of units for a
number of different products.
7/28/2019 designing_for_marking.pdf
14/18
Table 8.6.3. Suitable Materials for Various Marking Methods
Tags can be purchased preprinted.
Marking
method
Coating
materials
Base materials
Freehand Ink, paint, dye,
pencil, chalk,
crayon
Any clean surface capable of
being marked with some marking
medium, but nonslippery
nonpolished surfaces best
Contact printing
and noncontact
printing
Inks of various
types
Paper, cardboard, wood,
fiberboard, and other resilient
materials best with metal-type
process; all clean, smooth
surfaces suitable with rubber
type
Rubber stamp Ink Paper, metals, wood, fiberboard,fabric, plastics
Stencil Ink, paint, dye Paper, wood, metal, painted
surfaces, fabric, plastics
Silk screen Ink, paint Painted surfaces, metal, wood,
glass, plastics, paper, fabric
Etching None Glass, ceramics, all metals
Engraving None All machinable materials
Cast-in None All castable materials
Molded-in None All plastics and rubber
Branding None Wood, leather, fiber, plastics,
fiberboard
Hot stamping Special leaf-
pigmented
coatings carried to
Plastics, paper, fiberboard,
leather, wood, hard rubber
7/28/2019 designing_for_marking.pdf
15/18
the work by a
plastic film
Embossing None Sheet steel, aluminum, brass,
other formable metals, coated-
vinyl sheet
Coining None Low-carbon steel, aluminum,
brass, other formable metals
Stamp indenting None Steel, brass, aluminum, cast iron
(machined surfaces), stainless
steel
Decals Special paints,
inks, and dies on a
plastic film or
paper carrier
Any smooth-surfaced material
Tags Various materials,
depending on
which process is
used
Paper, cardboard, plastic, sheet
metals
Labels Same as for tags Paper, plastic sheet
Nameplates Same as for tags Various sheet metals, plastics
Programmable
stamper
None All machinable metals
Laser Coating not
required but maybe used to obtain
desired
appearance
Plastics, metals, ceramics
7/28/2019 designing_for_marking.pdf
16/18
7/28/2019 designing_for_marking.pdf
17/18
Figure 8.6.5. Low stress-inducing type for stamp-indented markings.
(Courtesy Pannier Corporation.)
Figure 8.6.6. High-legibility typeface enables each digit to be
identified even if there is only a partial impression. In the upper
piece, the top portion of each number is indistinct, and in the lower
piece, the bottom portion of each number is indistinct. In both cases,
however, all numbers are readable. (Courtesy Pannier Corporation.)
Table 8.6.4. Recommended Tolerances for Product Markings
Lettering height 10%
Lettering stroke 10%
Nameplate size (length and width) Normal tolerance, 0.4 mm (0.015
in)
Closest tolerance, 0.13 mm (0.005
in)
7/28/2019 designing_for_marking.pdf
18/18
Recommended