GLASS CONTAINER

DEFECT

Causes and Remedies

COPYRIGHT EMHEART GLASS

HERTFORD DIVISION

All Rights Reserved

TW0738/1191

INDEX

page

I. The examination of a Container i

II. The various Parts of a Container ii

III. Main Types of Sealing Systems iii

IV. Suggestions for Remedying Container Defects iv

V. Definition of Terms Used v

1. Defects Requiring immediate Action vi

Freaks 1

Split Finish 2

Checked Finsh 4

Crizzled Finish 6

Unfilledfinish 10

Choked Neck or Bore 12

Bottom Check 14

Thin Ware 16

Spike 18

Stuck Glass Particles 19

2. Finish Defects 20

Offset Finish 20

Bulged Finish 21

Chipped Finish 22

page

Broken Finish 24

Overpress 26

Corkage Check 27

Neck Ring Seam 28

Out-of-Round and Off-Gauge Finishes 30

Dirty of Rough Finish 31

Tear Under Finish 32

Bent or Crooked Finish 33

3. Neck Defects 35

Seam on Neck Ring Parting Line 35

Bent Necks 36

Long Necks 38

Hollow Finish or Neck 39

Dirty Neck 40

Pinched Neck 41

Danny Neck or Tear on Neck 42

4. Shoulder Defects 43

Shoulder Checks 43

Thin Shoulders 45

page

Sunken Shoulders 46

5. Body Defects 47

Stringy Glass 47

Hot or Panel Checks 48

Pressure Checks 49

Blank and Blow Mold Seam 50

Bird Cage (Bird Swing) 52

Brulse Checks 54

Letter Checks 56

Sunken Sides 57

Bulged Sides 59

Wash Boards 60

Cold Molds 62

6. Bottom Defects 64

Flanged Bottom 64

Thin Bottom 65

Thick or Heavy Bottom 67

Rocker Bottom 69

Baffle Marks 70

Swung Baffle 71

page

Wedge Bottom – Heel Top 72

7 General Defects 73

Brush Marks 73

Black Spots 74

Shear Marks 75

Oil Marks 76

Broken Ware 77

Loading Marks 79

Drag Marks 80

Lap Marks Or Wrinkles 81

Out Of Shape Ware 82

Uneven Or Bad Distribution 83

Dirty Ware 84

Stuck Ware 85

Blisters 86

Seeds 87

Cords 89

Stones 90

The Examination of a Container

A good container is a container that will go through the

customer’s filling line without causing any difficulty will carry

his product to the customer.

It is therefore essential that before a container is released for

scale from the glass plant . It successfully passes an insection

with standards set to meet the customer ‘s needs.

There are approximately one hundred defects which can

develop in the container during the production process, some

beyond the control of the operator , for example stones; but by

far the largest number occur either in the feeder or machine

operation.

It is important that all production personnel learn to recognize

the defects and understand what remedies to use in order to

eliminate them.

When a glass container fails on the customer’s filling line

because of a manufacturing defect, the reputation of glass

suffers, which results in a loss of customer good-will Always

remember; “The Price of a Quality Container is Eternal

Vigilance”.

Remedies offered hopefully give you a basic understanding of

defects and their causes. In some instances , several

remedies may be needed to correct the causes.

The Various Parts of a Container

In order to identify in a container. It is most useful to know all the

various types and parts of the container.

Types of containers

Narrow Neck Type Wide Mouth Type

Parts of a Container

The Finish

This is the top of the container above the neck ring parting line. It

includes:

The Sealing Surface

Bore

Bead or Color

The sealing device is in the finish (see next section), also the

bore or mouth for filling and emptying.

The bead or color is used to assist in transferring the parison

into the blow mold.

The Neck

The part which extends from the parting line to the curve at

the base of the neck.

The Shoulder

This extends from the base of the neck to the straight part of

the body.

The Body

The main part of the container which holds the product.

The Bottom

The part of the container on which it stands when upright.

Insweep

The curve between body and bottom which helps to improve

glass distribution and thus strength.

Push-Up

The center of the bottom which is raised up to provide a flat

surface on the outer edge of the bottom and thus provide a

firm seating.

Main Types of Sealing Systems

The finish is one of the most vital parts of the container. It

must be free of all serious defects to guarantee complete

sealing on the filling line. Some defects, such as crizzles on

the top sealing surface. May cause a container to leak slowly ;

which will only be discovered when opened and the container

to leak slowly; which will only be discovered when opened and

the contents found to be stole or to have spolled.

1. Top Sealing

Crown Cork – The sealing surface is on the

top the finish and used for narrow neck

containers being filled under pressure.

Thread or Lug – The sealing surface on the top

of the finish is closed by a screw type ca. Used

for wide mouth jars and narrow neck bottles.

2. Side Sealing

The sealing surface is on the side of the finish

and the cap is pressed on to seal the contents. It

is used for wide mouth jars in the food industry.

3. Cork Sealing

The seal is made on the inside of the

finish. It is used with narrow neck bottles.

Suggestions for Remedying

Container Defect

It is essential the the machine operator be able to isdentify

defects quickly and accurately ,and to know how to

remedy them. In this handbook all the major defects have

been listed , with an accurate description and a sketch

indicating the appearance of the defect and the position in

the container where it is most commonly found.

On the left page, the causes of the defect have been

listed, and in a corresponding position on the right hand

page are the remedies.

The operator should frequently examine the containers

passing along the conveyor from machine to stacker.

Approximately once every twenty minutes, but depending

on production speed, one container from each mold

should be set out and allowed to cool so that it can be

handled and thus examined more closely for defects. Don’t

waste these containers if they are not faulty and have not

been damaged – put them into the lehr.

Before correcting a defect , always remember the

following;

1. How many of the particular defects are rejects?

2. If corrected, what other types of defects may be

produced as a result of the adjustment made?

3. Only make adjustments when certain it will produce a

better container.

For Example:

If a few checks were appearing in the finish, do not

immediately reduce settle blow pressure or time .if it is

known that the finish r bore will then be outside

specification.

THINK BEFORE YOU ACT

Definition of Terms Used

Incorrect Too High or Too Low

Too Much or Too Little

Too long or Too Short

Blank Blank Mold

Mold Blow Mold

Parison The shape of the hot glass as it comes from

the blank mold.

Alphabetical List of Sections – Causes and Remedies

A. Feeder

B. Machine setup and Operation

C. Mold Equipment

D. Conveyor

E. Stacking Equipment

F. Inspection Equipment

G. Lehr Operation

SECTION 1

Defects Requiring IMMEDITE ACTION

Standards are set by the Quality Control Department

for most types of defects, but certain ones require

immediate action;

FREAKS

SPLIT FINISH CRIZZLED FINISH

CHECKS UNDER FINISH

UNFILLED FINISH

CHOKED NECK OR BORE

BOTTOM CHECK

THIN WARE

STUCK GLASS PARTICLES

SPIKES

If the operator is fully in control of the production on the

machine, containers with any of the eleven faults listed above should

never reach the annealing lehr.

Section 7 General Defects 90

Definition : Small pleces of refractory or unmelted batch materials.

Note : The production personnel cannot cure this defect, but it must be reported

immediately , as it is symptomatic of more serious trouble.

Some Possible Causes

1. Refractories from the furnace or foreheart are falling into the molten glass.

2. Batch materials are contaminated or incorrectly melted.

3. Furnace pull may be too high.

4. Flames impinging on furnace refractories.

5. Contaminated cullet.

STONES