Technology Partnerships by sol13192


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									    Progress through
    Technology Partnerships
    in Global Valve
    Casting Supply Chains

Progress through Technology
Partnerships in Global Valve
Casting Supply Chains
Because the procurement and processing of castings represents such a significant
proportion of finished valve costs, the performance of the castings supply chain can
profoundly influence the competitiveness of valve manufacturers. Valve manufacturing
costs are also heavily dependent on casting quality, which in turn impacts on safety,
reliability and performance. Casting delivery times, particularly for ‘specials’, is often
too long. Valve casting design, prototyping and production technologies have been
developed at Cti to improve the performance of the casting supply chain in all these
respects. Application of these technologies, especially in vertically integrated
operations, have resulted in major benefits for several progressive valve
manufacturers. Case studies quantify these benefits and illustrate how the dynamics
of the supply chain can be optimised. Particular reference is made to the supply of
one-off or small batches of castings. Exploitation of such proven technologies in
either the developed or low labour cost areas of the world can be facilitated by a
competent technical intermediary. Cti’s global experiences will provide a valuable
insight into possible future procurement strategies.

Castings Technology International       manufacturing technologies,              technologies and illustrates their
(Cti), Sheffield, UK, is a Member-      applications, structural integrity and   attributes with ‘real world’ examples.
based, non-profit distributing, ISO     performance have proved to be a          It also proposes a model for
9001-accredited organisation with a     strategic resource of value to many      intervention in the castings supply
budget of approximately £4.5m.          companies in a broad range of            chain which stimulates and facilitates
Employing 100 multi-disciplinary        sectors, but none more so than in the    the introduction of such technologies
personnel, the Company provides         valve sector. Castings are pervasive     to the mutual benefit of supply chain
R&D, consultancy and technical          commodities in much of                   partners.
services to casting producers and       manufacturing and engineering, but
users around the world. It is one of    valve manufacture is particularly            Valve Market Needs
the largest organisations dedicated     sensitive to the performance of the      In general terms, valve
exclusively to enhancing both the       castings supply chain, if for no other   manufacturers seek casting suppliers
performance of metal castings and       reason than the cost of the cast ‘raw    that can:
the competency of the casting supply    material’ represents such a high cost
chain.                                  of a finished valve (30-60% or           •     achieve short lead time to
                                        higher).                                       market of high volume parts and
With 5,000m2 of workshop space and                                                     exceptionally fast delivery of one-
production-scale, state-of-the-art      In the past, improvements in terms of          off or small batches of ‘specials’;
facilities, the organisation is well-   cost, quality and delivery
equipped to carry out market-led        performance have been achieved by        •     provide a range of alloys,
design and development activity and     enhancing traditional valve casting            especially for ‘specials’,
has achieved widespread                 production techniques. However,                embracing super duplex stainless
acceptance as a third-party technical   globalisation and restructuring in the         steels and high nickel alloys
intermediary – an “honest broker” –     valve sector has precipitated a                (Hastelloys®, Monels®, Inconels®
at the supply chain interface.          demand for new approaches to                   and Incoloys®);
                                        satisfy the emerging world order.        •     attain high integrity, i.e. defect
Its skills, experience, knowledge and
information in casting design,          This paper, therefore, focuses on              free castings;
materials, specifications,              new design and manufacturing
•       achieve consistent and accurate
        dimensions, i.e. minimum
        machining stock and
        consistency of form;
•       ensure minimum and consistently
        accurate wall thickness;
•       provide castings with good
        surface finish and lettering
•       facilitate achievement of low                                A 150mm control valve
        end-product manufacturing cost                               whisper cage and a
                                                                     300mm v-ball produced
        and low life-cycle cost.                                     by the Repliwax®
                                                                     Process at Brafe
Many valve manufacturers have                                        Engineering, Suffolk,
ensured cost competitiveness by                                      UK.
sourcing castings in low labour cost
countries, with quality and other
issues being addressed by procuring              strategy, no competitive advantage          the newly developed technologies
cast products in the proof-machined              is gained (and hidden costs can             more readily enable compliance with
or fully-machined condition.                     mitigate the benefits that low prices       the EU Pressure Equipment Directive
Sadly, failure analysis carried out in           in such areas of the world might            and, in addressing sustainability
Cti’s laboratories testify all too often         superficially at first imply).              issues, energy consumption per unit
that this is not necessarily a fail-safe                                                     of output has been reduced, as have
                                                 However, technologies developed at
strategy from the end-user’s                                                                 waste streams; the working
                                                 Cti specifically to address the market
perspective! Furthermore, if a                                                               environment has been improved
                                                 needs listed above provide the
predominance of valve                                                                        significantly and external impacts
                                                 opportunity to achieve additional
manufacturers follow the same                                                                minimised; and so on. These
                                                 benefits. They can maximise cost
                                                                                             attributes are highly relevant to those
                                                 reductions; they are intrinsically
                                                                                             companies for which ethical sourcing
                                                 capable of achieving high levels of
                                                                                             is a key component of procurement
                                                 quality and dimensional accuracy;
                                                 and they facilitate the attainment of
                                                 exceptionally short lead times, even            Technology Solutions
                                                 for products which are ‘customised’
                                                 with respect to design, material, etc.      1. Medium to high volume
                                                 Optimisation of such benefits is more
                                                 dependent on the competency of              The investment (lost wax) process
                                                 application of the technologies rather      produces near-net shape castings
                                                 than where in the world they are            with the highest quality, best surface
                                                 applied, although it goes without           finish and greatest precision. It is,
                                                 saying that advanced technologies           however, a costly process and is
                                                 coupled with low labour costs               limited to small components.
                                                 present a very attractive solution to
                                                                                             The Repliwax® Process increases
                                                 competitiveness issues.
                                                                                             the weight range of the lost wax
                                                 As a responsible organisation, Cti is       process. The technology embedded
                                                 well aware of legislative and               in the process achieves
                                                 regulatory agendas. For example,            manufacturing cost reductions by:
                                                                                             •     reducing material consumption
                                                                                                   and hence waste by as much as
                                                                                             •     increasing effective production
                                                                                                   capacity by as much as 35%;
                                                                                             •     reducing labour content and
                                                                                                   increasing productivity, i.e.
                                                                                                   lowering operating costs
    (Top): A polystyrene replica (pattern) for
    a 150mm ball valve                                                                       •     improving operational logistics,
    (Above): The lightweight, thin ceramic
                                                                                                   allowing faster and more flexible
    shell produced from the replica
    (Right):The resultant Replicast® casting.                                                      production.
    (Courtesy of Weir Valves & Controls,
    Huddersfield, England)
                                                                                         (Left): Assembled 150mm ball-
                                                                                         valves manufactured entirely
                                                                                         from castings produced by the
                                                                                         Replicast® Process at
                                                                                         CMS srl, Cernusco, Italy

                                                                                         (Below and far-left): Surface finish
                                                                                         (Ra) and total tolerance (ISO 8062
                                                                                         CT Grade) achievable with the
                                                                                         Repliwax® and Replicast®
                                                                                         Processes, compared with
                                                                                         traditional casting manufacturing

The process has been proved to be       to machining cost savings of 45%          Machining of polystyrene patterns for
a technically, environmentally and      or more.                                  one-off or small batches of castings
commercially sustainable, near-net                                                (up to 20, say) has been refined over
                                        Repliwax® and Replicast® are
shape technology, capable of                                                      the years at Cti. It is now well-
                                        complementary processes which use
reducing the cost of downstream                                                   established as a fast, cost effective
                                        common equipment and lend
processing of castings of a size                                                  way of producing ‘specials’ or
                                        themselves to high levels of
greater than otherwise possible with                                              prototypes. Many castings have been
                                        automation. The trend now is for
the lost wax process.                                                             produced using this approach,
                                        valve casting producers to adopt
                                                                                  especially in super-duplex alloys,
A major feature of Repliwax® is that,   both processes to provide flexibility
                                                                                  Monel®, etc. It combines the
as a ceramic moulding process,          and opportunity of choice to their
                                                                                  attributes of Replicast®, with the
inclusions, gas, hot-tears and other    customers.
                                                                                  capability of producing a casting in
casting defects associated with sand                                              as little as 5 days from receipt of a
                                        2. Low volume production and
moulding are avoided.                                                             functional 3D CAD file.
This is also a key feature of
Replicast®, a companion process         Two approaches
which similarly eliminates or           provide innovative
minimises the defects commonly          solutions to market
encountered on machining sand           needs for small batch
castings. It differs from the           manufacture. The first
Repliwax® Process mainly in that it     exploits high speed
substitutes polystyrene for wax         machining systems to
patterns. This enables even larger,     produce:
near-net shape products to be made      •   polystyrene
cost-competitively with sand                patterns to
castings.                                   manufacture small
This is because the technology, on a        and medium size
like-for-like basis, uses less than         castings by
50% of the same high quality                ceramic moulding;
ceramic as the lost wax process.        •   precision patterns           patterns
Ceramic material costs are just             and core boxes for           machined for
£0.07/kg of finished casting, less          sand castings,               a series of
even than the material costs of a           large and small;             75mm ball
sand mould.                                                              valves; the
                                        •   sand moulds and              thin ceramic
Furthermore, Replicast® valve                                            shell being
                                            cores directly, i.e.         poured; and
castings are typically 25% lighter          without the need             the ‘as-cast’
than a sand cast equivalent, which          for patterns or core         component
not only enables savings to be made         boxes.
in their manufacture, but also leads
                                                       envelope 2.6 x 2.6 x 1.2m)
                                                       to produce the castings in
                                                       a record time to high
                                                       standards of integrity and
                                                       dimensional accuracy.
                                                       Surface finish and lettering
                                                       definition exceeded all
                                                       expectations; after
                                                       assembly and painting, the
                                                       cast surfaces were
                                                       indistinguishable from
                                                       fabricated parts!                A sand mould machined at Cti in the
                                                                                        Patternless® Process

                              Large-scale,    Severn Glocon’s business is
                                              ‘specials’, and storing digital
                              machining at    machining data rather than patterns
                              Cti of          is commercially attractive.
                                              Geometry and lettering changes
                              valve           can be readily accommodated,
                              patterns and    especially for different cast
                              core boxes      materials, and storage and repair
                                              costs associated with conventional
                                              patterns are eliminated.
                                              The second approach Cti is
                                              pursuing for one-off or small batch
                                              production is that of Rapid
Modern, high-speed machining                  Prototyping, a generic term used to
systems can also reduce lead times           describe a range of technologies           Details of the machined lettering

for conventional pattern equipment,          which can quickly convert a digital,
while simultaneously achieving an            computer-based definition of the 3D
accuracy and precision of form               geometry of an object into a ‘hard
impossible by manual techniques. A           copy’ physical model.
large-scale machining system at Cti
                                             It is not the intention here to describe
(working envelope 4 x 2.5 x 1m) has
                                             the range of Rapid Prototyping
been used to meet otherwise
                                             techniques, suffice it to say that a
impossible lead times on numerous
                                             replica of the required casting can be
occasions. For example, patterns
                                             manufactured quickly in materials
and core boxes for 3 tonne and 6.5
                                             which lend themselves to conversion
tonne, 600mm Flowserve valve
                                             to a casting, notably from ceramic
bodies have been manufactured in
                                             shell moulds, within 5 days. For
half the time quoted by traditional
                                             example, wax or resin patterns within
pattern shops. Pattern costs were
                                             a maximum envelope of 500mm3 can
reduced by 20%, and subsequent
                                             be generated in a day or so. Beyond
projects on similar valve components                                                    The 610kg valve casting
                                             this size, the machining techniques
have been executed in just 10 days
                                             described earlier are more
with only 65 man hours of labour.
                                             appropriate – and more competitive
Even these gains have been                   – but Rapid Prototyping
eclipsed by a relatively new                 unquestionably offers a
technology - the Patternless®                complementary approach for smaller
Process – emerging from Cti’s R&D            valve castings.
programme. Elimination of patterns
                                             A case in point is a current project
and core boxes by directly
                                             involving the conversion of a 65mm
machining precision moulds and
                                             cryogenic gate valve body for
cores from blocks of sand provides
                                             industrial gas manufacture.
unprecedented opportunities for one-
                                             Previously machined from solid, the
off or small production quantities.
                                             component is now to be produced by
For example, rather than fabricating         the Repliwax® Process, the potential
two large valve bodies, Severn               for ‘end product’ cost savings having
Glocon of Gloucester, UK, took               been demonstrated using wax
advantage of the facilities at Cti (a        patterns grown directly and                The assembled 300mm angle globe valve
                                                                                        (courtesy of Severn Glocon Ltd.,
purpose-designed sand-mould                  automatically from a 3D CAD                Gloucester, UK)
milling machine with a working               geometry in just 17 hours.
                                                            with respect to              commensurate lost opportunities for
                                                            manufacturability as         quality improvement, cost reduction
                                                            a casting. Neglect of        and delivery performance have sadly
                                                            this issue puts at risk      blighted valve casting supply chain
                                                            ‘right first time’           relationships for many years.
                                                            manufacture which, in
                                                                                         These issues are raised here
                                                            the case of one-off or
                                                                                         because there is little sense investing
                                                            small batch production,
                                                                                         in new valve casting manufacturing
                                                            especially in ‘difficult’
                                                                                         technologies if no attention is paid to
                                                            alloys, destroys any
                                                                                         the design of parts to be produced
                                                            prospect of achieving
                                                                                         specifically by those technologies.
                                                            the cost and lead time
                                                                                         The design must reflect the process
                                                            benefits associated
                                                                                         capabilities in order to extract
                                                            with the technologies
                                                                                         maximum benefit; merely
                                                            described herein.
                                                                                         reproducing the geometry of a sand-
                                                                It is furthermore        cast part by Replicast®, for example,
                                                                essential that, in       will ‘short-change’ the opportunities
                                                                parallel with            for cost and quality improvement to a
                                                                assessment of valve      degree which brings a process with
                                                                performance by the       so much potential into disrepute –
 A 1420kg, 300 x 500mm angle body casting produced by the
 Patternless Process for Severn Glocon
                                                                application of Finite    and sadly, too many examples of
                                                                Element Analysis         consequential failure exist.
                                                                (FEA) and
Cti has embarked on a major                                                              Supply Chain Optimisation
                                                 Computational Fluid Dynamics
initiative to develop the ‘enabling’
                                                 (CFD), simulation of the casting        It is noteworthy that penetration of all
technologies to exploit Rapid
                                                 process is conducted to ensure the      these techniques has been greatest
Prototyping, not only for fast
                                                 design is optimised with reference to   in vertically-integrated operations,
manufacture of ‘specials’ but also to
                                                 the specific casting manufacturing      where the internal supply chain
accelerate ‘time to market’ of new,
                                                 technique selected.                     interface is seamless and due
high-volume product ranges. This
entails significant investment in                The value of such concurrent or         recognition is given to the importance
facilities to demonstrate the capability         simultaneous engineering is well-       of design. Typically the driver for
of Rapid Prototyping on ‘real world’             established in other engineering        adoption of a new technology has
products and to benchmark its                    sectors and Cti is engaged in a major   been the development of a new
performance against alternative                  project (e-valves) aimed at             range of valves.
techniques – such as machining of                promoting and facilitating design       Achieving the same benefits in an
polystyrene or wax.                              interaction across the valve casting    environment of independent
                                                 supply chain interface.                 customer-contractor relationships is a
Design Optimisation                         The project will deliver the potential       far greater challenge. Cti is well-
                                            value of concurrent engineering by           aware that promoting the benefits of
The benefits of these techniques,
                                            ensuring that the selected casting           technology to casting manufacturers
especially those for small batch or
                                            manufacturing technique is                   – technology push – will get
one-off production, can be
                                            capable of meeting the                       nowhere. Only by demonstrating the
maximised when a 3D CAD file
                                            requirements specified during the            potential to casting users can a
exists. This saves time and ensures
                                            design process.                              market pull be developed to stimulate
that the valve manufacturer receives
the precise geometry specified.             While this may seem blindingly
                                            obvious, the market failure to               Most success in promoting adoption
Availability of a 3D CAD file also
                                            recognise this dependency and the            has been achieved where a strong
facilitates optimisation of design
                                                                                         relationship exists between a valve

                                                                                                    A Rapid
                                                                                                    Prototype wax
                                                                                                    casting and
                                                                                                    cryogenic gate
                                                                                                    (Courtesy of
                                                                                                    Valves Ltd,
Concurrent design optimisation of a 50mm control valve body at Cti: 3D solid model; finite element analysis illustrating stresses in the body due to internal
pressure; and simulation of casting solidification showing isolated (red) regions of liquid metal. (Courtesy of Northvale Korting Ltd., Leicester, England).

manufacturer and casting supplier.                         etc. and all other casting                      •    ongoing technical support to the
This applies regardless of where the                       processing operations to                             partnership to ensure best
casting supplier is located (it is a                       establish opportunities for cost                     practice is maintained; to
perverse aspect of the digital age                         reduction through supply of cast                     troubleshoot any issues which
that the technologies developed to                         product forms with appropriate                       arise from time to time; and to
compete with low cost sources of                           attributes;                                          facilitate continuous
supply can so readily be exploited in                                                                           improvement, especially in the
                                                     •     an audit of supplier operations to
those areas of the world).                                                                                      light of any new developments.
                                                           benchmark capability against
Typically, Cti acts as a ‘technical                        global best practice criteria held              Cti has worked long and hard to
intermediary’, using its facilities and                    in Cti’s databases;                             overcome adversity in the casting
competencies to minimise risk and                                                                          supply chain. Where constructive
                                                     •     definition of mismatch between
cost and to provide underpinning and                                                                       and mutually beneficial relationships
                                                           customer expectations and the
ongoing technical support. Whereas                                                                         have been developed, quite massive
                                                           prospect of the casting supplier
a conventional foundry produces                                                                            gains have been realised and Cti has
                                                           meeting those expectations with
castings by a specific process, Cti                                                                        played no small part in bringing such
                                                           existing technology and current
has available the entire range of                                                                          relationships and commensurate
                                                           casting designs;
processes and cast materials (air                                                                          benefits about.
and vacuum melted) and so is in a                    •     optimisation of existing or new
                                                                                                           This has been done in enlightened
unique position to determine and                           valve casting designs and/or
                                                                                                           self-interest, because our collective
demonstrate which process provides                         manufacturing technologies to
                                                                                                           future is inextricably linked. As
the best, integrated solution to a                         achieve the lowest cost solution
                                                                                                           casting production migrates
particular need.                                           to the ‘wish list’ criteria and to
                                                                                                           eastward, valve manufacture will
                                                           achieve maximum valve
A number of market leaders and                                                                             surely follow. Our co-destiny,
                                                           functionality and reliability;
several small but progressive valve                                                                        therefore, should stimulate us all to
manufacturers have exploited the                     •     demonstration in Cti’s                          preserve what we can of our
opportunities that this capability                         production-scale operations, at                 manufacturing base; and we are able
presents in partnership with their                         minimum risk, cost and time, the                and willing to help. But we cannot do
casting suppliers. The most                                improved match between                          so without the market pull that the
successful arrangements have been                          expectation and the capability of               market alone can provide.
predicated on Cti’s assistance with:                       the improved design and/or
                                                           technology solution to deliver;
•    the development of a ‘wish list’                                                                      Repliwax®, Replicast® and the Patternless®
     with respect to procurement and                 •     specification of supplier                       Process are Registered Trade Marks of
     processing of castings in order to                    development plans embracing                     Castings Technology International. Certain of
     identify, characterise and quantify                   the plant and equipment,                        the technologies described in this paper are
                                                                                                           patented and may only be used in accordance
     key issues;                                           materials, skills, etc., necessary
                                                                                                           with the terms and conditions of a licence
                                                           to operate to the proven supply                 agreement.
•    a detailed review of machining
     strategies; jigging and fixturing,

                                     For further information please contact Dr Mike Ashton at
                            Castings Technology International, 7 East Bank Road, Sheffield, S2 3PT, UK
                                          Tel: +44 (0) 114 272 8647             Fax: +44 (0) 114 273 0852
                          Email:                     Web:

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