ITP 234 Midterm 2

The first three printing processes involve:

1) Application of ink to a printing plate/cylinder. 2) Transfer of the ink to a substrate.

thermoforming design guidelines

1) Include draft angles in side walls. 2) Design the part with a flange. 3) Use a realistic draw ratio. 4) Use radii and/or chamfers in corners and edges. 5) Undercuts

modeling strategy plan

1) divide (complex 3d shapes into simpler peices) 2) understand (how simpler shapes can be created) 3) use bolean operations 4) translate (steps 2 and 3 into solidworks features)

concentric mating is applied between __________

2 cylindrical faces ( forces axes to become collinear

helix

3d curve on a conical or cylindrical surface that would become a straight like if the surface unrolled on a plane

flange

A flat lip around the part perimeter (i.e., flange) is a by-product of the die cutting process. The flange creates an edge that provides structural rigidity and a flat surface for heat sealing or for snapping a lid.

die cutting

A tool, die cut, is used to cut shapes of thin materials.

Printing may include:

Adding graphics Application of barrier/protective coatings Waxing Lamination

injection molding radii

An inside radius should be at least 50% of the wall thickness. An outside radius should be the nominal wall thickness plus the inside radius (150% of nominal wall). Sharp corners at the base of bosses and ribs can be stress concentrators. The edge where a boss meets the nominal wall should be rounded to reduce the sharp corner without increasing the wall thickness enough that it creates a sink mark problem. The radius at the base of a boss should be 1⁄4 of the nominal wall with a minimum radius of 0.015".

Radii and chamfers

Avoid a sharp three-sided corner by using a radius or chamfer. The radius at the bottom of the draw is most critical. The deeper the part, the larger the radius or chamfer required.

Die cutting may include:

Cutting Creasing or scoring Debossing Embossing Hot stamping,

draft angles

For parts that are formed into a female mold with a texture allow one degree of draft for every thousandth of an inch of texture depth. With parts formed over a male mold allow three degrees of draft as a minimum

Extrusion Blow Molding

HDPE, PP; opaque, translucid; bottles, jars

Receiving

In a roll or sheet from a paper mill or supplier. Sheeting a roll in-house may be a separate operation.

in mold labeling

Initially designed for blow molding, though developments using injection molding or thermoforming with reel-fed systems have increased the efficiency of the labelling process.

injection molding Wall thickness

Maintain a wall thickness of less than 5mm because thick walls can lead to long cycle times and poor mechanical properties. Keep wall thickness constant and uniform. Avoid large variations in wall thicknesses in order to simplify flow pattern and minimize variations in shrinkage that can lead to warpage. Avoid abrupt changes in wall thickness, as this can create stress concentration areas that may reduce a part's impact strength. Wall thickness changes should have transition zones that reduce the possibility of stress concentrations, sinks, voids, and warp.

blow molding

Manufacturing process used to mold hollow parts.

Four primary printing processes:

Offset lithography Flexography Rotogravure Digital

Factors used in the selection of printing processes

Order quantity Complexity of the graphics Quality requirements Substrate Desired ink coverage Make-ready times Cost of tooling (plates and dies)

Typical materials used for blow-molded packaging parts:

PET, HDPE, PP

Typical materials used for injection-molded packaging parts:

PET, LDPE, HDPE, PP, HIPS

Injection Blow Molding

PET, PP, HDPE; transparent, opaque; bottles, jars for hot-filled products

Injection-Stretch Blow Molding

PET, PP; transparent, opaque; bottles for carbonated beverages

Typical materials used for thermoformed packaging parts:

PET, PVC, HIPS, PP, PC

Blow Molding: Design Guidelines

Part shape should have a plane of symmetry to be used as parting line. The parting line divides draft angles for both sides. Provide release draft angles on side walls of at least 2-3 degrees. Provide radii in corners and edges. A common radius specification would be 0.5 mm (0.02 in). Provide a bottom recess so the container is stable.

Warehousing and Distribution

Printed, glued, folded, and collapsed cartons are case packed and palletized before proceeding to warehousing prior to distribution. Cartons/blanks may be packed into cartridges compatibles with high speed packaging machinery.

Carton Converting Operations

Receiving Printing Die cutting Finishing Warehousing and distribution

Carton Converting Operations

Set of operations in a typical carton or corrugated converting plant. Processing paperboard and corrugated fiberboard to create a product

Injection Molding: Sink Marks

Sink marks occur where there is a substantial variation in the thickness of the plastic walls. Keep wall thickness constant.

draw ratio

The deeper or taller the part, the heavier the starting gauge of sheet required

______ _______ are required for Injection Blow Molding

Two molds

Undercuts

Undercuts are an inward-facing flange, but they can include other features that are not parallel to the direction of pull out of the mold. Undercuts increase tooling cost, but the cost increase is significantly less than if you were to incorporate the undercut into an injection molding tool. They increase strength and rigidity and hide trimmed edges. Normal undercuts require movable section of the mold

Finishing may include: "Anything that is done to the blank after die cutting and before shipping."

Windowing Gluing Combining with other substrates Couponing Coding

benzier curves (splines)

a computational method to represent smooth curves between two points (anchors) and a few control points (weighted handles) that specifies the tangency and curvature at given points

assembly

a file that contains two or more parts

component

a part or sub-assembly inserted into an assembly

tangent mating is applicable between _________________ or _____________

a planar and cylindrical surfaces or two cylindrical surfaces

tangential point

a point at which a line touches a curve but does not intersect it

inflection point

a point on a curve at which the sign of curvature changes

vertex

a point where two or more curves meet forming an angle

mating conditions are relationships that ____ & _____ components together in an assembly

align and fit

triad tool

allows for more precise movements

sub-assembly

an assembly inserted into another assembly

Extrusion blow molding can produce bottles with _______________

built-in or molded hollow handles

Runners

channels that distribute molten plastic to various cavities in a multicavity mold.

first constraint

coincident mate between two frontal faces, removes three degrees of freedom

most common mating conditions

coincident, concentric, tangent, coplanar, parallel, perpendicular faces, offset faces

solid modeling is a ________ & _________ _________ of a precisly enclosed and filled volume

complete and unambiguous representation

Parts are referred to as ______

components

form creation

constrained by the manufacturing processes and the materials associated to the processes

base component

constructing an assembly begins with bringing in a base component, selected because of its central role

second constraint

coplanar mate between the right side faces of both components

third constraint

coplanar mate between the top faces of both components, removes one degree of freedom

swept boss

creates a solid by sweeping a profile along a specified path (requires a profile and a path)

first step in understanding basics of manufacturing

develop feasible design solutions

mating

each component needs to be oriented and placed relative to other components in the assembly. mates remove degrees of freedom form a component, reflect physical behavior

mates are stored in the ______ _______, they can be edited or deleted

feature manager

parts and their assembly are directly related through ____ ______

file linking ( changes in component affect the assembly and vice versa)

use ____ to help select small features

filter

by default, the first part placed in the assembly is _____ in space

fixed

thermoforming

forming heated plastic sheets into containers by shaping them into or around a mold

sketches should be ____ ______ to prevent unexpected results when editing them.

fully defined

constraints

geometric relations are used between elements of components for mates

thermoforming 3 basic steps

heating, forming, trimming

three main types of axonometric projection

isometric, dimetric, trimetric

click and drag with the ____ mouse button to translate

left

Sprue

main channel through which molten plastic enters the mold.

conic sections

mathematical curves calculated at the various possible intersections of a plane and a cone

Draft Angles injection molding

minimum of 0.5 degree per side draft in order to accommodate easier ejection from the mold

flexible thermoforming containers

more suitable for low-cost products and for simple tray configurations, but do not offer the same degree of structural protection as the semi-rigid trays

isometric projection

most common axonometric projection, axes share a common scale

translation

movement along X,Y,Z

orthographic projections

multiview and axonometric

profiles

no limit to the number of profiles, do not have to be on parallel planes, must be either all open or all closed

guide curves

no limit to the number, must be either all open or all closed, must not cross each other, no two curves can have the same guide points, can extent beyond the first and last sections

third angle projections

object is placed in the third quadrant (US)

parallel projections

oblique and orthographic

For Injection Blow Molding ____________ is created by injection molding, then the parison is blown in a second mold.

parison(preform)

bottom-up modeling

parts are created first and then added to the assembly file

graphical projections

perspective and parallel

first angle projection

place object in first quadrant (Europe)

A __________ or film is inserted in an open mold and held in place via vacuum ports, electrostatic charge, or other method. When the mold is closed, __________ enters into the mold, _____________________ permanently within the finished part.

pre-printed label, polymer resin, encapsulating the label

mating conditions

relationships that align and fit components together in assembly

click and drag with the _____ mouse button to rotate

right

rotation

rotation around X,Y,Z

primitives

simplest solid objects used for boolean operations

Gate

small opening through which the molten plastic enters the mold cavity.

curve types

straight lines, conic sections (circle, hyperbola, ellipse, parabola), helixes, bezier curves (splines)

semi-rigid thermoforming containers

structurally self- supporting, provide good physical protection and are suitable for multicomponent applications

constructive solid geometry

technique used in solid modeling that allows a modeler to create a complex surface or object by using boolean operations to combine simpler objects

feature

term used to describe the elements of a model. they are created in sequential order and represented by a hierarchical tree

Principles of projection purpose

to create object views

thermoforming typical

trays, lids, blisters, clam shells

an assembly contains ____ or _____ ____

two or more parts

coplanar mating is applied between ___________ and forces them to lie in the same plane.

two planar faces

axonometric projection

type of parallel projection use to create a pictorial drawing of an object, where the object is rotated along one or more of its axes

parametric

used to describe the ability to update the geometry of a model by modifying its dimensions

Web-fed format:

uses entire rolls of substrate.

Sheet-fed format:

uses individual sheets fed into the press.

Injection Molding: Design Guidelines

• Use draft angles • Use radii • Uniform wall thickness • Under cuts