n e w s 6

6swen

2

3

4

6

7

8

9

10

12

2001

R u b b e r I n j e c t i o n

S u m m a r y

SummaryJuly 2001

New productsin Düsseldorf:REP’s future-proof approach.

Process developmentCreativity and Practicality

Special machinesWhen Standard becomesCustomized

Bi-compound injectionSimultaneous or Sequential Injection

LSRA Multipurpose Press

TPRA Flexible Solution

V68Lowered Working Height

Heating platens with distributed power rods

H48The Horizontal Presses

Current developments

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 1

e p a r t md e n t e p a r t md e n t

wen

3

editoe d i t o

The job of the Process Development Department: advi-sing the customer on the mold design and kinematicsrequired for a given piece. The Department defines thebest molding conditions and carries out tests to determinethe ideal setting values. The Department plays a key advi-sory role, backed by the experience of the thousands ofstudies conducted since its creation, in drawing up spe-cifications for special presses, always in close collabo-ration with the customer

Major equipment andhuman resourcesIt is the daily task of ten specialized per-sonnel to devise customized answers tothe technical challenges posed by Rep’scustomers. To do this, they have all theresources of a first-class test laboratoryas well as a database containing over11,000 previous technical studies.Working at an international level, theApplications Department relies on aworldwide network of external resources:materials and ingredients manufacturers,chemists, research institutes,moldmakersand tool-makers.The Department works very closely withthe Special Machines Department toensure the customer is provided with theoptimum machine, whatever the specifi-cations or the range of applications. Similarly, close and diversified collabo-ration with manufacturers enables theteam to demonstrate their creativity,but without losing sight of the practi-calities of production. Talent and expe-rience: an essential combination whendeveloping your new applications.

Rep will of course be taking part in

the K’2001 Exhibition; this will be a

flagship event for the rubber and plas-

tics processing industry, in an econo-

mic context giving Europe a prepon-

derant role.

Rep will be presenting use of G8

technology across their product range

together with their ability to adapt this

range to highly varied uses in terms

of both materials and applications.

Versatility and rapid adaptation to

given requirements are the key crite-

ria that have guided the development

of the products that we shall be sho-

wing at this exhibition.

And indeed, in a fast-changing indus-

trial context, it would appear essen-

tial to be able to adapt one’s pro-

duction facilities rapidly and at lower

cost to new high-performance confi-

gurations.

That, then, is the thinking behind the

design of the G8 range: modular,

built as a standard unit able to take

more than 50 accessories listed in

the catalog options and as many

configurations as there are possible

uses, whether as initially configured

or modified by the user throughout

its machine life.

Have a good exhibition everyone!

Bruno TABAR

s

The test laboratory: a truly impressive facility

- Several presses representing the range or instrumented, perma-nently available for a range ofoperations (evaluation of mixes,mould testing, the development of molding methods, refining toolsand equipment, demonstrationsand so on).

- Over 40 molds

- Data acquisition facility

- Rheometer linked up with thepress by Curetrac 2®

- RepNet-win®

ProcessDevelopment

Departmentcreativity

and practicality

To meet special requirements, theDepartment can adapt, or indeed crea-te, a specialized press around the partto be molded (closing force, platensize, type of mix, etc.). It can also meet special requests suchas the adaptation of a machine to thespecifications of each customer at thesame time as using and retaining REP’sstandard subassembly technology. For this purpose, a development-orien-ted team, consisting of 15 engineersand technicians skilled in a range ofareas – engineering, hydraulics, auto-matic process control and software –designs and turns out the adaptationsand the special machines required,always with the same objectives of per-formance and reliability as those mar-king the whole of the REP range.

Special Machines departmentwhen standardbecomes customized

As part of their ongoing quest to constantly improve their response to the customer, some 15 years agoREP created a Special Machines Department which has since proved to be a highly successful initiative!

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 2

wen

4

Today, the simultaneous or sequential injection of two materials produces exceptionallyhigh-performance moldings. But do they justify investing in a machine devoted solely tobi-compound injection? To resolve this dilemma, Rep has developed fully flexible andreversible machines whose versatility goes hand in hand with performance.

The advantages of bi-compound injection Bi-compound injection makes it possi-ble to produce parts combining severalfunctions by optimum use of the pro-perties of the materials involved. Forexample, some electrical parts consistof a conductive or semi-conductingmaterial as well as an insulant; here,the purpose is not only to combine thetechnical properties effectively butalso to optimize costs: by obviating theneed for assembly operations or elseincorporating a low-cost material into apart in proportions that ensure that therequired performance is not in any wayimpaired.

For example:• Bi-compound hoses, whose inner

surface is required to ensure water-tightness using minimum thickness,with a thicker outer surface designedto provide strength.

• Engine mountings on which eitherdifferent dynamic properties can becombined in a single part, or thedynamic component can have astronger casing.

• Electrical parts made of a conduc-tive or semi-conducting material andan insulant.

s

5

Three methods of injectionParts of this type can be produced by: - two consecutive injections into twocomplementary cavities;

- simultaneous injections into two dif-ferent cavities or into two separatecavities;

- simultaneous (or staggered) injec-tions into a single cavity (as with theV48, to be displayed at K'2001).

Injection is possible either directly intothe mold or via a special cold runnerblock (CRB) incorporating several mate-rial circuits.

Rep solutions The two injection units are standardRep units with all their well-knownadvantages. One is located above the press, theother is mounted on a separate framebehind the closing unit whichincludes columns designed to pick upthe mould nozzle bear-down loads.G8 process control is designed to inte-grate management and control of thesecond injection unit. This additional

function does not in any way impairother aspects: compatibility with thestandard options is maintained andthe operator interface remains stan-dard. There are the same control func-tions on both injection units, with se-parate displays of the relevant controlparameters.The hydraulic unit is compact; its over-all dimensions are hardly greater thanthose of a conventional press: a sin-gle motor drives two separate pumpsto feed both injection units. Two materials can be injected simulta-neously with separate control of theparameters governing the volume,speed and pressure of each injection

unit, thus ensuring total material flowflexibility.

Flexibility a priority The press is not designed solely for bi-compound injection: it offers the possi-bility of going from simultaneous tosequential injection or simply using oneinjection unit according to requirements.The principle of bi-compound injectioncan be applied to all vertical G8 presses,irrespective of the size of the frames andinjection units.

- Shot capacity: 2 x 740 cm3 at 2000 bar- Closing force 1600 kN- Platen dimensions 430 x 510 mm.

CODAN Hoses (UK)

versatilityand flexibility

a c h i n em s a c h i n em s

BBii--ccoommppoouunnddinjection

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 4

wen

7

a c h i n em s

s

6

The increasing success of the LSR process LSR (Liquid Silicone Rubber) is beingincreasingly used to optimize costs:cycles are shorter and packing in large

drums reducesrestocking times;and the low pres-sures requiredfacilitate bothmold cavity fillingand the duplicatemolding of fragileinserts at thesame time asreducing flashes.

Solutions for greater versatility The presses developed by REP, that areused to inject LSR, are not limited sole-ly to liquid silicone. Our purpose is tomeet occasional requirements, or toensure diversified production.

The press is versatile: with the sameinjection unit, it is possible to injectrubber in strips or viscous siliconepegs by adapting the standard stuffer.At the same time, it is possible to havepresses designed solely for liquid sili-cone injection, in which case the injec-tion unit no longer has an extruder.

To facilitate the change from a conven-tional mix to an LSR, the press’s soft-ware is adapted to select the desiredprocess together with all the relevantparameters.

The mold is adapted with regard tofeed, and if a cold runner block is used,the nozzle can be fitted with valves. On the press to be shown at K’2001,we are incorporating a pumping devicesupplied by DOPAG which feeds in thetwo constituents which are then mixedin the static mixer. By collaborating withexperts in the field of pump manufac-ture, means we can always provide themost effective solutions.

The mechanical parts are easilyremoved to reconvert to a conventionalpress.

Why TPRs?Some parts are changing from a conven-tional elastomer to a thermoplastic elas-tomer, for the following reasons:

- Cost optimization.Not only can the waste be crushed

and re-used, but the shorter cyclesmean increased productivity. However,the material costs more and thereforeits selection has to be decided on acase-by-case basis. A TPR molding will not usually have

the same shape as a rubber molding,and to perform the same function ithas to be redesigned.

- Material performance.Depending on the application, the

properties of the molding may be betterthan with rubber; for example, TPR hasa good friction coefficient and obviatesthe need for flocking in body sealingapplications.

- The TPR “feel”The “soft to the touch” effect, whichtoday is highly rated, particularly in thecosmetics industry, is yet another rea-son for using TPR.

Total adaptation of the injection unit We can adapt an injection unit to theTPR process. At K'2001, we shall beshowing a V17 with a Y125 injectionunit, although this application hasalready been achieved on largerinjection units. With regards to the input of material,a hopper is connected to the extruderscrew intake. On the smallest of theREP injection units (Y125), a smallcylinder has been added to mix thegranules, at a variable frequency, toensure that the screw is completelyand effectively filled. The screw’s L/D ratio is maintained,thus most conventional materialscan be processed. Additionally,REP’s system of function separationmeans that the material can beprocessed along the entire length ofthe screw, ensuring completely uni-form mixing conditions even in thecase of very different volumes. Ascrew/piston system would notensure uniform mixing during the

same cycle and could not guaranteethe same mixing conditions. The compression rate can vary from1.25 to 2.5, depending on the appli-cation.One adaptation consists of eliminat-ing oil control and using electricband heaters, which heat the injec-tion unit up to a maximum of 250ºC,with independent multi-zone control. Depending on the type of material, aneedle type shut-off nozzle andspring opening at a given pressurewill be used. A nozzle whose openingis controlled by the press automaticcontrol system can easily be adaptedfor the purpose.

Compactness and flexibilityThe main components of the injec-tion unit have been retained. Switching back to a process usingconventional mixes by a specificchange or by using another injectionunit. Or gain, this facility can easilybe retrofitted. With identical shot capacities, theREP injection units used for this typeof application are more compactthan the injection units used forplastics.

For several years now, REP has been operating fairly successfully on the liquid siliconemarket. As a result of close collaboration and ongoing consultation with a number of cus-tomers, today REP can bring you presses that are fully adapted to the LSR (liquid siliconerubber) process but which retain all of their rubber injection capabilities.

Today, there are a number of alternatives to rubber for both technical and economicreasons. TPRs (thermoplastic rubbers) are among these increasingly used alterna-tives. REP has integrated the properties of the TPRs to develop an effective and need-less to say a flexible solution (like all REP products).

for changingeasily from rubber to liquid silicone and vice versa

LSR TPR Where TPR isessential

rreepp provides a flexible answer

ZHEJIANG YONGGU Liquid Silicone Connector(China)

DECOSEAL Body Seal (Canada)

- Shot capacity : 740 cm3 at 700 bar(LSR)740 cm3 at 2000 bar(Elastomers)

- Closing force 1600 kN- Platen dimensions 430 x 510 mm.

- Shot capacity : 125 cm3 at 1560 bar

- Closing force 255 kN- Platen dimensions 300 x 300 mm.

a c h i n em s

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 6

we sn

9

The REP closing principleThe REP three-step closing systemensures a constant opening stroke,whatever the height of the mold. Forpresses with a closing force of 400tons and over, REP offers an alternativesolution with a constant working height(1040 mm on the V68 with no slidingplate) and a variable opening stroke.

Why a lowered working height? Because this enables the mold-ings to be released at a con-venient height for the operatorwith no need for a platform or apit, and facilitates installation.Additionally, locating the pressesat floor level means they canbe moved more easily shouldthe molding shop need to bereorganized.

Working principleThe new system consists oftranslating a clamping block

fixed to a plate and not connectedto a clamping piston. The movementis driven by a cylinder fitted withhydraulic shock absorbers, ensuringfast, smooth movement. Guidance isprovided by linear guides protectedfrom dirt by guards located on themoving platen.

A constant height, minimumspace requirements The height of the moving platen at theend of the opening stroke is constant,irrespective of the thickness of themold. Space requirements of thepress at floor level remain the same.The new closing system fits into stan-dard casing and remains compatiblewith the mechanical / hydraulic ejec-tor options on the moving traverseand the sliding plate. The basic features of the press havebeen retained: compatibility with theequipment used on previous pressgenerations, opening strokes, etc.The mold adjustment range, however,has had to be reduced (involving easyadaptation in the case of certain verythin molds).Major work has been carried out onthe mechanical and control compo-nents so as not to affect cycle timeadversely. The clamping and unclamp-ing operations have been optimizedand the time required for this functionhas been cut in half.

A uniform temperature offers numerous advantages,including the following - better quality, by reducing the tole-rances of the moldings;

- gains in productivity: as the peripheryof the mold is heated to the samedegree as the center, additional cavi-ties can be used. Vulcanization timecan also be reduced.

A comprehensive solution REPs approach to the problem was towork on a complete system with amold and not solely on the platen.REP took account of the customer’soverall needs, without limiting itselfjust to the machine itself.Temperature dispersion is caused byheat losses around the periphery ofthe mold and the platen. The distri-buted power heating rods used in thisnew concept compensate for theselosses by greater heating at theedges of the platen. In other words,we use distributed power heating rods(calculated by finite element simula-tion combined with the relevant testsand measurements) to make up forthe heat losses.

Advantages - The use of an insulant around themolds is both very restricting andexpensive, hence optimization includeddoing away with the insulant. - The new concept uses a single areaper platen with the probe as near aspossible to the cavities; the advan-tage of this is enhanced control of theeffective area and simpler setting andadjustment. This obviates the needsfor tricky fine tuning with each newmold, unlike the multi-zone systemwith a probe in the platen, whichrequires different set values per zonein order to achieve uniformity in thecavities. - This facility is easily retrofitted atlow cost to existing presses.

- The distributed power rods are com-patible with Thermotrac®2 andenhance all of its tried and provenadvantages.

FlashA completely uniform platen does notgive a uniform mold. REP corrects thisto ensure that the mold cavities areall at the same temperature. Roddimensions can also be optimizedaccording to mould thickness andcharacteristics by use of the simula-tion module developed for this study.

With an injection press, ergonomics are an essential factor of productivity. The V68 press, withits lower working height, is a perfect example.

The characteristics of the moldings depend on their state of vulcanization, that is to sayon vulcanization temperature and time. A difference in temperature between mold areascan significantly affect the uniformity of the characteristics of the moldings and alsonecessitate a vulcanization time that is less than optimal.

with lowered working height:mold release in easy reach

q u i p m ee n

Heating platenswith rreepp distributed power

rods to ensure a uniform temperaturein the mold cavities

Temperature reading on the cavities of the saucer mold mounted on a V68 fitted with heatingplatens with distributed power rods.

Finite element calculation of the mold par-ting line temperature

VV6688

8

- Shot capacity : 1500 cm3 at 2000 bar- Closing force 4000 kN- Platen dimensions 630 x 800 mm.- Working height 1040 mm

t q u i p m ee n t

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 8

we sn

10

e v e l o p m ed n t

To meet the primary requirements of itscustomers, REP has made a point of:- integrating G8 process control intothe horizontal presses, because of itsperformance, its user-friendliness andoverall ease of use;

- reducing cycle time;- increasing clamping force from 160 to190 tons on the H48;

- making the brush configuration moreflexible (different systems of moldstripping).

A new design for enhanced performance The hydroelectric frame and the panelingare in the tradition of the G8 verticalrange. Access to the hydroelectric set isfacilitated by the installation of two largedoors which also help to reduce thenoise level. The brush system is modular and offersnumerous possibilities:- single brush;- double brushes; - brushes with the possibility of integra-ting an ejection or gripping system.The brush system is versatile; designedwith a rack and pinion system, it ensu-res easy adjustment according to thetype of mold together with rapid assem-bly and disassembly.The press can be fitted with threehydraulic ejectors, the central onehaving a longer stroke than on the G7models.

Faster, but with no addedspace requirement The dry cycle time has been reduced by25% following modifications to themechanical elements, the change toG8 process control and the use of ahigher-capacity hydraulic pump. REP has maintained its reputation forcompact horizontal presses.The emphasis has been placed onaccessibility. With the H48, one ormore conveyors can travel under theframe for removal of the moldings onthree sides of the press, or a containercan be installed under the press.The ergonomics have been improved,with the PC and the control panel loca-ted as close as possible to the mold. Maintenance will be much easier, asmaximum use is made of standard G8components (electrical, hydraulic, etc.).

GG88

- Shot capacity : 740 cm3 at 2000 bar- Closing force 1930 kN- Platen dimensions 450 x 450 mm.

The standat Düsseldorf

2001

1 - Distributed power heating rods

2 - V68 lowered working height 1500 cc / 2000 bar

3 - V48 bi-compound 2 x 740 cc / 2000 bar

4 - V17 TPR 125 cc / 1560 bar

5 - V48 LSR 740 cc / 700 bar

6 - H48 740 cc / 2000 bar

11

12 3 4 5

6

H48Horizontal presses

with process control

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 10

Ease of use: • More effective

on-line assistance

• Integration of “exotic” languages

• Reduced starting time

Performance: • More effective injection speed

control thanks to use of a newCPU combined with still moreefficient control loops.

• Reduced control software cycletime (< 10 ms) ensuring redu-

ced machine response timeand reduced dry cycle time.

These capabilities will becomeavailable in the 1st quarter of2002.

In early 2002, we shall also beintroducing new G8S processcontrol (‘S’ for ‘simplified’), desi-gned for machines with a simpleconfiguration but achieving alevel of performance equivalentto that of G8 process control.

Current developments

r u b b e r i n j e c t i o n

G 8 A U T O M A T I C P R O C E S S C O N T R O L

12

This is already highly regarded for its ease of use and excellent perfor-mance, and current developments will achieve further significant prog-ress in these areas:

N E W M A C H I N E S

We are pursuing the integration of G8 technology into other models in theREP range, with the following machines:

REP Groupwww.rep.tm.frFranceREP INTERNATIONAL15, rue du Dauphiné - B.P. 36969960 CORBASTel. : +33 (0) 4 72 21 53 53Fax : +33 (0) 4 72 51 22 35E-mail :techassistance@repinternational.frcommercial@repinternational.fr achats@repinternational.fr

SACOMAT Rue de Bramafan B.P. 273230 BARBYTel. : +33 (0) 4 79 72 88 88Fax : +33 (0) 4 79 72 74 15E-mail : sacomat@repinternational.fr

Germany REP DEUTSCHLAND Sauergasse 5-769483 WALD-MICHELBACHTel. : + 49 (0) 6207 9408.0Fax : + 49 (0) 6207 6632E-mail : repdeutsch@aol.com

United-KingdomREP MACHINERYPetersfield AvenueSLOUGH BERKS SL2-5EATel. : +44 (0) 1753 57 09 95Fax : +44 (0) 1753 53 88 41E-mail : sales@repuk.co.uk

ItalyREP ITALIANACorso Vercelli 1310078 VENARIA (TO)Tel. : +39 (0) 11 42 42 154Fax : +39 (0) 11 42 40 207E-mail : sscamangas@repitaliana.inet.it

U.S.A.REP CORPORATION 8 N 470 Tameling CourtP.O. Box 8146BARTLETT, Illinois 60103-8146Tel. : +1 847 697 7210Fax : +1 847 697 6829E-mail : repmail@repcorp.com

BrazilREP INJETORASDE BORRACHA Av. Kennedy, 54 Sala 05 2° andarJd. Do Mar – SAO BERNADO DO CAMPOCEP : 09726-250 SAO PAULO BRASILTel. : +55 11 4125 7950Fax : +55 11 4125 6525E-mail : repinj@terra.com.br

ChinaREP BEIJING OFFICEJunefield plaza – Room 1305N°6 XuanwumenwaiXuanwu districtBEIJING 100052Tel. : +86 10 63 10 14 47Fax : +86 10 63 10 15 90

Vertical machines: V 38 Replacing the V37 (clam-ping force 100 T) but with amachine configuration providingfront and rear access as with aV48 and the use of a new G8Selectro-hydraulic unit. These models will have an injec-tion capacity of 400cc or 1000ccat 1500 bar.

V 88 New machine with a clam-ping force of 800 T and the follo-wing basic characteristics: • 1000 x 1000 heating platens• Injection capacity 2000 to

8500 cc at 1500 bar• Working height < 1000 mm,

irrespective of mold thickness

Horizontal machines: H 58 Development of the H47and H48 based on the H57(250T): • New clamping system• G8 process control

and hydraulics• New frame and paneling

C-frame machines: Creation of a new model with clo-sing and injection from the top andwith the following basic characte-ristics: • Clamping force 40 T• 435 x 300 mm heating platens• Distance between platens

500 mm

These models will be on the marketduring 2002.

Phot

os :

Luc

y in

the

Sky

[Anglais]MP REPNEWS 09/2001 3/01/02 10:23 Page 12