06 Schlotterbeck M Requirements and Solution Proposals for Optimal Design of the Zinc Diecasting Process1

8/10/2019 06 Schlotterbeck M Requirements and Solution Proposals for Optimal Design of the Zinc Diecasting Process1

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1 Oskar Frech GmbH + Co. KGAuthor: Martin Schlotterbeck

Martin Schlotterbeck

Oskar Frech GmbH + Co. KG

73614 Schorndorf-Weiler /Germany

Requirements and solutionproposals for optimal design

of the zinc diecasting process


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Short presentation from the Frech company

Introduction and intentions for thispresentation

Facts and suggestions for an optimal layoutof the process

Summary

We have prepared the following for you:


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Headquarters: Schorndorf-Germany

17 subsidiaries and

numerous international agencies

approx. 700 employees worldwide

Frech Worldwide

Product Lines

Hot chamber diecasting machines Cold chamber diecasting machines Dies


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Hot chamber

Hot chamber diecasting machines Locking force range from 50 kN 9300 kN

Machine types: hydraulic, fully electric, hybrid

Different technology levels

Application: Pb, Zn, Mg

AutomationHeating and cooling unitsRemoval technologySpraying technologyVerification systems

Transport systemsMelting and holdingtechnology

Die Technology -


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Cold chamber

Cold chamber diecasting machines Locking force range from 1.25 MN 50 MN

Application: Al, Mg

Machine types: hydraulic, Realtime Control and Standard Shotend

Different technology levels and

process techniques: (Standard, VACURAL)

Heating and coolingunits

Removal technology

Spraying technologyVerification systemsPlunger lubricationTransport systemsFurnace technologyDie Technology


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Service

Services

Training

Technical consulting

Condition Monitoring

RSD

Worldwide service network

Replacement components Overhaul expertise

Replacement and ConsumableParts

Simulation Test casting (Prototyping)

Engineering

Overhauls


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Introduction and Intentions

The use of the latest methods such as FGS, optimized machineprocesses and new alloys can only be employed efficiently when the

basic design of the process is correct.The design of a die with regard to flow and heat technology is still notyet a matter of course. Passive, economical and highly efficientventilation systems are not yet common practice.

A fast, repetition-accurate diecasting machine with real-time control,

pre-filling, camera system, etc. can be optimally utilized when goodprocess design is also taken into consideration as part of the whole.With this presentation, we would like to demonstrate or at least remind

you of the requirements of the optimized zinc diecasting processwith our specific solution proposals in order to improve upon any

untapped potential in the diecasting process.


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The most exciting part of the success story ofFrech machines is its continuation!

From the Schorndorf technology museum And more than 50 years later

For an optimal casting process, you need a reliable, repetition-accurate andextremely dynamic machine. The modular design of modern machine technologyhas the advantage that it can adapt to infrastructure and requirementsaccordingly.

STOPSTOPSTOPSTOP


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The control system -- the cockpitof the casting system!

Today, the control system is the foundry personnel's cockpit. Gone are hand wheels

and cams for manual adjustment work because manual settings are unfortunatelynot always reproducible and hardly proofable. Today everything is visualized via thecontrol system. A range of adjustment aids are available for optimal configuration.Setup work is shortened, data is saved and personnel can comfortably set up themachine. A complex casting profile can only be adjusted and monitored withintegrated measurement technology (casting graphic).

STOPSTOPSTOPSTOP


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Casting parameters are theparameters of success!

Correct casting parameters are not easy to determine, as the casting processis very complex. Adjustment profiles help the operator to graphically andgeometrically depict, calculate and monitor the casting process.

STOPSTOPSTOPSTOP


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Casting parameters are theparameters of success

A complex casting profile can only be adjustedwith integrated measurement technology(casting graphic).

STOPSTOPSTOPSTOP

With older control systems, you canadjust a machine but cannot monitorthe process.

An experienced caster "hears" whether the casting process sounds good. However,he cannot hear the gate velocity and pressures, etc. Casting graphics have been thestandard at Frech since the mid 1990's and have been continually upgraded forease of adjustment. Parameters such as filling times, plunger velocities and

pressures can only be correctly determined and monitored using these graphics.


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The shot end: The engine of progress!

Real-time control shot endwith servo hydraulics in delivery andclosed position control circuit.

Standard shot endwith conventional proportionaltechnology in the intake.

Various shot ends are available according to the requirements of the cast part.The highest demands are met with the real-time controlled "RC" shot end.Absolute reproducibility from casting process to casting process is guaranteed.A freely programmable, process-oriented plunger course makes nearly any shotprofile possible.

STOPSTOPSTOPSTOP


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There is a patent (no. EP 1284168 A1)against too much air!

"Pre-filling"The system is filled with meltup to shortly before thenozzle tip.

Air inclusions are the most frequently occurring casting defects. With the"prefilling" system, the casting system is nearly completely filled with melt.Through simultaneous execution of the piston and locking movement, the cycletime is additionally shortened.

STOPSTOPSTOPSTOP

"Standard"The melt in the castingsystem is at the metallevel.


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The die must also be protected!

Long service life is above all a question of die design. However, usefulmachine features, such as an active, sensitive die protection system of themachine with "teach function," for example, also protect the die during the

closing process.

"Standard"

A die protection system which ismanually adjustable via the

pressure is too slow and imprecise.

"New FRECH Standard"

Intelligent die protection system withmonitoring of the pressure curve

previously determined in learning mode.

STOPSTOPSTOPSTOP


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Melt zinc at a high level!

The quality of a component begins with the melt. The charging side is separatedfrom the removal side by separate chambers, for a clean melt and a stable,

uniform melt level.

STOPSTOPSTOPSTOP

"Standard 1-chamber furnace"

with unstable melt level and variablecasting profile as a result.

"Multichamber furnace"

with constant melt level in order to enable

an absolutely uniform melt dosing fromshot to shot.


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Melt zinc and not your money!

23.5 %1.23 kW/h4.01 kW/h56.2 kW/hNew cover withinsulation

--5.24 kW/h73.35 kW/hWithout cover

Savingsin %

Savings in comparison,without cover

Averageconsumption

Measurementover 14 hours

Furnace type:ZC 50/180*

STOPSTOPSTOPSTOP

The newly developed cover not only saves energy but also reduces oxide formationand protects the melt from outside contaminants.


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The correct die temperature lies somewherebetween hot and cold!

High product quality, low production costs and high process reliability usuallycannot be achieved without temperature-controlled dies. The greatest primarysource of error is a less than optimal die temperature. A controlled heat flow in themelt, precise die filling, directed solidification and long die service life all require aprofessional temperature control system, customized to the die.

STOPSTOPSTOPSTOP

Preheating with a burner

does make the die hot, but is not areproducible parameter and does notreplace a temperature control system.

Temperature control systems for the dies

for heating and cooling with water or oil, formaintaining the required temperature and formeasuring and monitoring.


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We are spraying with excitement!

STOPSTOPSTOPSTOP

This retrofit set (2 wires, one plate) isnot available from FRECH.

The spraying process must already be taken into consideration during the

designing of dies and processes. The spraying systems must be conceptualized,selected and considered. Spraying devices are continually misused in order toeliminate insufficient thermal die designs, whereas only a fine separating filmshould be applied. A wide selection of spraying devices, tools, spray nozzles anddie lube containers are available. We can provide you with more information.

Point spray 15

Flat spray 70

Modular fine spraying technology, adaptableas desired for all spraying tasks IS availablefrom FRECH.


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Service lives of dies: the longer the better!

Aluminum Cold chamber

from 150,000 cycles

Magnesium Hot chamberfrom 400,000 cycles

Zinc Hot chamber

from 600,000 cycles

The service life of the die depends on: flow speedsGate velocities, pressure peaks, cycle times, die lubes, die temperature control,thermal change stress, mustering (preheating) and the alloy. The manufacturing

method of the die, the geometry of the contour and the die material used arealso decisive.The die designer must know and master these arguments. If they areincorporated into his considerations, the expense for an optimally designed dieis relatively minor.

to 350,000 cycles

to 1,000,000 cycles

to 2,000,000 cyclesSTOPSTOPSTOPSTOP


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Massive problems from "unstable dies"!

A massive and thick die plate has a greater bending resistance than 2 thin

plates, at about the same material costs. The more stable die plate can betterabsorb pressure peaks. Its greater thermal capacity serves as a heat reservoirand can better equalize temperature fluctuations. Flash development occurswith weak, bendable dies. These causes of defects are frequently mistaken forlocking force being too low. An unstable die cannot be repaired.

STOPSTOPSTOPSTOP

Unstable die structure with many thinplates, weak frame and supports.

Stable die structure with a few thickplates, solid frame and strong supports.


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The nozzle tip: bottleneck!

The nozzle tip, a bottleneck? Yes! Unfortunately, this is often too small. Theresult is casting problems. The diameter A is decisive for the usable section, forthe velocity of the melt and the quantity of flow! A nozzle tip that is too small isthermally inefficient and throttles the machine capacity. Large nozzle tips areavailable from FRECH.

A

STOPSTOPSTOPSTOP

One often sees "mini nozzle tips."They throttle capacity, are prone tofreezing up and are unfavorable withregard to flow technology.

The correct mathematical design of the diebegins with large nozzle tips matched to therequired casting capacity.


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Sprue bushing: save on cooling,costs cycle time!

There should never be a shot bushing without cooling. There is usually space to

be found for a small cooling channel. The transition from the nozzle tip into theshot bushing is critical with regard to thermal efficiency and therefore must betemperature-controlled. If this area is too hot, the sprue taper sticks. The castingprocess is interrupted and the cooling time must be extended. Not the coolingtime of the part, but the cooling time of the cross sections determine more often

the length of the cycle time.

A "rod sprue" without the possibilityfor placement of efficient cooling.

STOPSTOPSTOPSTOP

Thermally and flow optimized distributor andsprue bush.


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Don't take too many stages at once!

CB

A

D

100%

90%

81%

72%

d

C

B

A

A general decrease of the sections in the flow direction is required so that themelt always remains under static pressure and air inclusions are therebyavoided. After a direction change in the runner, the sections should be reducedby approx. 10% per deflection.

STOPSTOPSTOPSTOP

Differing sections and a bottleneck onthe distributor are unfavorable withregard to flow. Correctly staged sprue system.


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Unfavorable

Blind flow:

The melt front is continually swirled in.Contaminated melts cannot be collected, sincethis area is flushed out time and again.

Runner: the flow's the thing!

A flow-optimized runner with sections correctly tailored to the castingvolume can be produced at neutral cost.

Flow-optimized runner:

Short flow paths and small deflection angles

STOPSTOPSTOPSTOP

correct

Done correctly


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Gate design: "limitless potential!"

The design of the gates is the most important fundamental for good parts quality.Experience and an understanding of the filling process are important for a solidgate design. The die filling simulation is an important element for predicting thecharacter of the filling. The very precise statements made by today's die fillingsimulations should always be applied for complex parts.

STOPSTOPSTOPSTOP

Flow-optimized variant:

For round and oval geometries, but also for a widevariety of other configurations, a casting streamaligned to the center is the ideal solution.

Standard Tangential sprue:

The classic has its limits. The casting stream isdeflected on the outsides. As a result, there is riskof confluence of the melt opposite the gate.


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Small gate, big damage!

Cavitation occurs when localized melt velocity is too high. In subsequent section

expansions, a vacuum occurs which causes the melt to vaporize. Damagesoccur due to the condensation of melt vapor. Correctly graduated sections tothe gate and gentle curves in the sprue system as well as gate thicknessesgreater than 0.35mm are required. The filling time in particular (2nd phase)must be monitored by the machine.

STOPSTOPSTOPSTOP

Variant for high gate section:

The correct gate section must be calculated. Thegate velocity should be approx. 40m/s. 60m/s shouldnot be exceeded.

Cavitation risk due to localized gatevelocity being too high:

A thin, smaller gate section increases thevelocity of the melt.


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The air must go!

Air is usually not displaced by the melt flowing in at high velocity, but rather enclosed

and compressed at the specific casting pressure. Good and sufficient ventilationalready begins at low pressure in the 1st phase. The ventilation pathways areguided to the outside; the melt is aligned toward the center. Connections to theventilations are thereby reached only at die filling end. With correctly placedventilations which can be securely removed, sufficient ventilation is possible.

STOPSTOPSTOPSTOP

Without ventilation system:

Overflow channels are often designated asventilation systems. However, there is noconnection to the outside, unfortunately.

With ventilation system:

Here in the form of a wash-board milled directlyin the die insert. An excellent alternative to the"chill block."


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One can never have enough!

The temperature control should generate surface temperatures which are asuniform as possible. This requires a sophisticated channel system for optimalthermal transfer, in accordance with the complexity of the parts. The overheatedregions in the die extend the cycle time and increase spraying agentconsumption. Areas with shrink porosity and low part stability result due to slow

cooling.

STOPSTOPSTOPSTOP

Simple temperature controlled channelsystem:

Too little exchange surface in the die inserts

is insufficient for efficient thermal transfer.

As a general rule, the more channels the better.

Shielding of the die hollow space area is achievedthrough correspondingly placed temperaturechannels.


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Small section, high loss!

Unfortunately, section bottlenecks are often unknowingly built into differentpoints in temperature control connections. Deflections, section bottlenecks andlong inlets throttle the volume flow and consequently the energy transfer of thetemperature control unit.

STOPSTOPSTOPSTOP

Improvized assembly of pipes andnipples.

Do not leave it to chance. Correctlydesigned connections are the work of the diedesigner.


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The calculated values from die design can be entered directly on the machine,with only a few manual steps. The machine is adjusted using these values.Feedback on the die design is thus possible. Retrieve this valuable info beforeyou start a new design.

Feedback for die designers

STOPSTOPSTOPSTOP

Crack the safe and get the feedback! The most important casting parameterscan be calculated, monitored andevaluated directly on the machine.


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Everyone knows the price, but not the value!

At 10% cycle time savings and a service life increase of only 16%, 30% greater die costscan be amortized. Even greater savings are possible by reducing the rejection rate, which

is not even mentioned in this comparison.

0.083

0.304

0.452

0.093

0.274

0.452

Die service life

600,000 cycles

Costs 100,000

Die service life

700,000 cycles

Costs 130,000

Manufact. costs /part 0.839 Manufact. costs /part 0.819

Material costs Material costs

Machine costs at

30 s cycle time

Machine costs at

27 s cycle time

Existing

diedesign

Optimiz

eddiedesign

STOPSTOPSTOPSTOP

Ti l f d h Kli k


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Summary

My notes have perhaps not been revolutionary innovations for you. Butit is precisely the simple things which are not in our direct focus.

This, my field report from practical experience shows as an examplewhere the greatest potentials for improvement still lie.

Often, a great deal can be accomplished here with very little.

This presentation can also be used as a kind of checklist.

Go through your foundry next week and take a look at the topics I havecompiled.

Any improvement is better than postponed perfection.

I wish you the best success.

Tit l t f t d h Kli k


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A great deal more information about diecasting technology as awhole, from 5 tons hot chamber to 4400 tons cold chamber,

can be found at:

[email protected]

Tel.: 0049 (0)7181/702-0

Oskar Frech GmbH + Co. KG

Schorndorfer Strae 32D-73614 Schorndorf-Weiler

Germany

Tit l t f t d h Kli k


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Thank you for your attention.

Martin Schlotterbeck

Documents

06 Schlotterbeck M Requirements and Solution Proposals for Optimal Design of the Zinc Diecasting Process1