|
| |
Solidworks |
 |
Click pic to left to see Solidworks
design
Another great Feature of Solidworks
is the ability to be able to show our
clients an actual 3D
representation of their product in the
design stage, the client does not need
to have any added software in order to
view their product.
Click Here
to see the design in action. |
|
| |
Mastercam |
 |
By using Mastercam
we are able to prove out designs prior to production,
this ensures accuracy and well as decrease our turn
around time for our customers.
left: Pre-Production Cutout Path |
 |
Not only do we test production designs,
but we run pre-tooling design checks,
this ensures production tooling is correct
prior to investing in production tooling
left : Pre-Production tooling |
 |
Here is an example of fault tolerance,
notice the reddish area, this shows a possible
flaw in the tooling path Prior to production.
This flaw was fixed immediately and this
product went into production flawlessly
and within the required time span. |
|
VACUUM FORMING DESIGN CONSIDERATIONS
This method is the most commonly used technique
for forming plastics sheets into custom shapes.
It is also the most economical method.
Dimensions - Tolerances
Please see “Standard
Manufacturers’ Tolerances” below
for guidelines.
Draft Angles
Draft on male (positive) molds should be 2°
- 5°, maybe 0° to ½ ° in
special circumstances. Draft on female (negative)
molds may be 1° - 4° depending on texture
of mold and surface finish. Draft angles are
necessary to prevent the part locking onto the
molds.
Radii and Fillets
Radii and Fillets are required on most vacuum
formed parts. They should never be less than
the minimum part thickness. They should be 2-4
times the expected wall thickness when extra
strength and thickness of parts are required.
Material Thickness
Material starting thickness will always be thinner
when the part is formed and will vary upon the
general size, height, depth of pockets and other
complexities. If you have any questions on starting
thickness specifications or any other design
consideration, please contact the C&K Plastics’
sales engineering people.
Pressure Forming
Design Consideration
Pressure forming is used where the injection
molded look is desirable, namely greater definition,
variety of surface textures, smaller radii,
molded vents or pockets. It is generally more
expensive than vacuum forming, but tooling costs
are only a fraction of other methods. Molds
that are female (negative) should be aluminum
and preferably water-cooled. Parts designed
for short runs or prototype may be made of epoxy
or wood, depending on complexity of the shape
and depth of draw.
Dimensions - Tolerances
Please see “Standard
Manufacturers’ Tolerances” below
for guidelines.
Draft Angles
Draft angles for female (negative) aluminum
molds should be 2° - 6° to prevent lockup
of part in mold. Deep parts or complex configurations,
texturing on the tool side, may require more
draft angle.
Radii and Fillets
Radii and Fillets may be less than in vacuum
forming. Sharp corners may be attained on shallow
draw areas. Keep in mind that larger fillets
and radii make stronger, stiffer parts and create
thicker corners.
Material Thickness
As in vacuum forming, material starting thickness
will thin when part is formed. However, the
amount of thinning will depend upon shape, size,
depth of draw, radii and fillets. For any special
design considerations in pressure forming, please
contact C&K Plastics’ sales engineering
people.
Standard Manufacturers’
Tolerances Design Considerations
Tolerances will vary from part to part, depending
on the materials, size, shape, numbers of cutouts
and other configuration possibilities.
However, as a general rule of thumb, the following
tolerances should apply off the tool surface.
Formed Dimensions:
± .020” for the 1st 12”
± .002” for each additional inch
Hand Trimmed Dimensions:
± .030”
CNC Dimensions:
± .015”
CNC and hole to hole tolerances sometimes must
be increased due to the coefficient of thermal
expansion. Our CNC and other computerized trimming
machinery are capable of cutting to within ±
.0005”, however, plastic does move due
to temperature changes. The formula is as follows:
Length (inches) x temperature difference
(F°) x .00005”
Example: 20” at 90°F will move to
19.98” @ 70°F
20” x 20°F x .00005 = .020”
Please keep this in mind when
designing any plastic part. Slots and over-sized
holes work well.
|
