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Focusing core binder needs.

Inside This Story

* Design for Six Sigma translates customer requirements into meaningful, verifiable coremaking design characteristics.

* Coremaking parameters that maximize casting characteristics are identified to achieve a more robust design.

* Experiments designed on the basis of those characteristics determined that binder level had the greatest effect on the greatest number of properties.

Those familiar with phenolic urethane coldbox (PUCB) binders are well aware of the sheer number of variables that need to be understood and manipulated to achieve the desired property and performance requirements of a good core and a good casting. Potential differences and commonalities resulting from binder composition, sand varieties, test methodology, and equipment and test parameter settings must be understood and carefully controlled.

The purpose of this article is to help metalcasters identify the right binder product for a given metalcasting application while maximizing data value and minimizing subjective data interpretation using the Design for Six Sigma (DFSS) concept.

Defining and Measuring

One of the most important elements in DFSS is to clearly understand the needs of file metalcaster (and the end-user) and the level of importance assigned to each need. This process is known as determining the "voice of the customer." There are maw ways of deciphering the voice of the customer, such as market research, surveys, customer meetings and operation audits. A well executed voice of the customer investigation gives fundamental insights into the customer's operations and needs, which, if met, lead to products and services that provide superior value and customer satisfaction.

When we apply the voice of the customer process to metalcasting facilities and their expectations for sand binders, a number of factors need to be considered.

1. Defining the properties of the sand core or mold that result in a good and profitable casting often is difficult.

2. Good aesthetics in sand cores and molds are no guarantee of casting quality.

3. The definition and measurement of what makes a good core is non-standardized and subject to opinion.

4. The properties of the PUCB binder required to make a good core and improve it are similarly subjective.

5. The interaction of PUCB binder's core production properties vs. core quality properties are complex.

6. Other variables in the core manufacturing process can interact with the PUCB binder's properties and affect the core and casting quality.

Voice of the customer is a process that aims to remove the ambiguity of subjective customer requirements and determine objective operation requirements. The metalcaster is concerned with reducing casting defects, finishing costs, core machine and tooling downtime, raw material and process cost of cores, wastes and waste costs and environmental, health and safety costs, as well as increasing speed of production and improving post-casting sand removal.

Using QFDs to Determine Influence

Quality function deployment (QFD) charts can indicate the level of correlation of process requirements to end products. Level 1 (Fig. 1) depicts a metalcaster's requirements, which can be correlated with features referred to as critical to quality (CTQ) characteristics. These measurements are used to benchmark, monitor and improve operational efficiency. The metalcaster may use these measurements to differentiate the "better" binder from the "good" binder.

The QFD Level 2 (Fig. 2) correlates metalcaster CTQs with PUCB core and coremaking properties. Typically, varying levels of correlation range from low to high. If the assigned high correlation strength is real, then improvements to one or more of the identified PUCB core and coremaking properties should have a measurable contribution to meeting the metalcaster's CTQs.

The QFD Level 2 also requires that test methods to probe the PUCB core and coremaking properties are assigned and capable. In many instances, established and standardized test methods will provide adequate information. However, depending on the specific improvement needed, special test methods may have to be developed. Gage repeatability and reproducibility determines the amount of variation present in the test as a proportion of the total measurement variation and can be used to assess the level of risk of acceptance of bad data or product or rejection of good data or product.

Using QFDs to Find Critical Materials

Now that the measurement systems have been defined, the next step is to take the PUCB core and coremaking properties and correlate them with the materials used to make the core/mold (Fig. 3). The materials typically involved in PUCB coremaking are an aggregate such as sand and (sometimes) sand additives, a binder characterized by its composition, a refractory coating and the suspension solvent from which it is applied, and an amine catalyst.

The PUCB binder system has two parts. Part 1 typically is comprised of a phenolic resin, solvents and performance additives. Part 2 contains isocyanate, solvents and performance additives. The cured binder is best described as a phenolic-urethane polymer which has a profound impact on a core's mechanical properties, resilience to atmospheric conditions and performance when interacting with liquid metal. Depending on the type of phenolic resin and the isocyanate, a large spectrum of different phenolic-urethane polymers can be created. Solvent technology also is being viewed as critically important to the performance of the binder, both at coremaking and during subsequent stages of storage and at casting. Solvents make up 20-40% of the total binder composition and provide the basis for many property variations.

Performance additives generally account for a small portion of the entire binder composition but result in significant effects. The variety of binder performance additives has grown over decades of PUCB process development. Many additive solutions are fixes for the trade-off properties created by older additives, As these are very cosily, this re-assessment of the technology either does not include the effects of additives or keeps their effects to a low and standardized level within any comparison.

The fact that a typical phenolic-urethane bonded core may consist of 99% sand and only 1% binder suggests that the sand source and quality play a major part in the properties of the core and possibly have an impact on the casting. The binder, however, is expected to compensate for any shortcomings that may result from the choice of sand.

In the fourth and final step of the present example, which aims at linking customer requirements to verifiable product (e.g. PUCB binder) and processing characteristics, the interactions of coremaking process controls with PUCB core and coremaking properties are considered (Fig. 4).

In terms of coremaking process controls and variations, resin addition (e.g. the binder level) is known to have an important effect, as does the geographical location of the core machine due to extreme variations in ambient conditions. Many of the other process controls were important issues that have a history of causing problems, so their control would be considered basic good metalcasting practice anywhere in the world. Mixed sand flowability is a more complicated property, not only related to the sand type and quality, but also to binder viscosity. By formulating the binders to one target viscosity, the impact of differences in sand flowability was kept to a minimum.

Based on the above, five coremaking variables were determined to be of immediate interest and global impact:

* sand;

* binder solvents;

* binder polymer;

* resin addition;

* location of manufacture and test.

Testing Critical Characteristics

Design of experiment techniques provide an approach to efficiently designing complex, large-scale experiments which will improve the understanding of the relationship between product and process parameters and the desired performance characteristics.

For the performance comparison of different PUCB binders on different global sands, the following factors and levels were applied in the study:

* Sand source--Four subangular silica sands with AFS GFN 50.

* Binder solvent package--Aromatic hydrocarbon solvents and ester solvents (S1 and S2).

* Phenolic-urethane polymer--Results from combining phenolic resin with isocyanate (B1 and B2).

* Resin addition--Two levels: 1% and 1.5%, measured as weight percent of binder based on sand, Part 1 and Part 2 applied in a ratio of 1:1.

* Location of test piece manufacture and test--three test laboratories in the U.S., Europe and Asia. The coremaking and casting tests employed to comparatively evaluate the performance of the binders were identified in Fig. 2:

* Coremaking

* Tensile and transverse strength

* Tensile strength at 24 hours

* Three hour mixed sand bench life tensile strength

* Amine consumption and curing efficiency

* Release and resin wipe-off

* Hot distortion

* Casting

* Gray iron erosion wedge casting

* Gray iron penetration casting

* Gray iron warpage block casting

* Aluminum shakeout casting

The casting surface finish was judged from both veining and penetration castings. Veining, penetration, erosion and surface finish were rated visually using a scale of one to five, with one as the best and five as the worst. Warpage was measured as deflection of the core cavity in the resulting casting.

The raw data gained from the experiments were analyzed statistically using analysis of variation techniques. A design factor with a large difference in contribution to the total variation from one level to another indicates that the factor is a significant contributor to the performance characteristic in question.

Studying the Impact

Binder level has a profound impact on core strength, both immediately and after 24 hours. The higher binder level results in higher strength. No effect of binder type on immediate strength was observed. Little variation was noticed as a result of different sands. The greatest level of variation stemmed from the test location (i.e. the lab).

Both the effect of the binder level and test lab location were similar in the 24-hour strength evaluation. However, the binder did reveal trends resulting from both polymer and solvent composition. Compared to in, mediate strength development, the variability of the sand impact appears to increase over 24 hours, without assignable cause at the present time.

In looking at warpage and erosion test results, it is interesting to note that while the effects of sand choice and resin addition were similar in both sets of tests, the choice of phenolic-urethane polymer and solvent package had different effects. Higher binder level resulted in reduced warpage and improved erosion performance of the core.

Analysis of Variation

The objective of the variation calculations is to assign a proportion of contribution to the total measured variation by each factor.

All factors had a significant effect on at least one and usually more coremaking properties. The binder level had the largest effect on the greatest number of properties, while the variation in sands had the smallest effect on many of the properties.

The variation between test locations was consistent in most properties.

The contribution to variation arising from the casting tests and evaluation of casting properties resulted in a very different picture. Some casting properties were mostly sand-specific, while others were affected by all factors. The contribution of binder technology and binder level was significant in properties such as erosion resistance and warpage, and the binder level clearly dominated shakeout. Veining proved to be completely independent of PUCB binder choice and addition and largely dependent upon the sand.

For More Information

"Testing Keeps Pace with PUCB Binders," R. Showman, K. Schumacher and R. King, MODERN CASTING, February 2005, p. 20-23.

The Six Sigma method.

Six Sigma is a statistical measure of variation and a business philosophy that signifies that an organization is committed to understanding its customers' requirements and providing products and services at a level of no more than 3.4 defects per million opportunities as a quality target. DFSS is the application of Six Sigma principles to the design and development of services and products, including their manufacturing and commercialization support processes. DFSS encompasses six phases.

1. Define--Identifies the opportunity, strategic drivers and scope of the project.

2. Measure--Focuses on customer requirements, performance targets and approach to data collection.

3. Analyze--Addresses the concepts, design criteria and product development to meet critical quality and performance targets.

4. Validate--Evaluates the successful design, as well as potential weak points, which may be susceptible to failure and determines product/manufacturing capability.

5. Implement--Defines the full scale production, supply chain management and commercial aspects of the product placement with the target customer(s).

6. Control--Monitors and establishes long-term capability and manufacturability of the product.

Mark Stancliffe is technology development manager, Jorg Kroker is global technology director and Xianping Wang is senior staff chemist for Ashland Casting Solutions. Stancliffe is based in Kidderminster, England, and Kroker and Wang are based in Dublin, Ohio.
Fig. 1. QFD Level 1 depicts how metalcaster requirements
or needs can be correlated with features referred
to as critical to quality (CTQ) characteristics.

 Customer CTQs/Measurements

 Casting
 scrap/
 inspection Core
 Importance cost strength/
 to Customers, and time quality
 1, 3 or 5

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

Customer Requirements 1 2

 1 Reduce casting finishing 5 9 9
 costs
 2 Reduce the raw material 5
 cost of cores
 3 Reduce casting defects 5 9 3
 4 Increase speed of core 5 1
 production
 5 Reduce wastage and waste 3 9 9
 costs
 6 Reduce core machine & 5 3
 tooling downtime
 7 Reduce EH&S Impact 3 1
 8 Increase rate and 3
 completeness of sand
 removal, post cast
 9
10
Technical Priorities
 Relative Importance 117 110
 Importance, % 14.6 13.8
 Rank 1 2
 Measurement units $ psi

 Customer CTQs/Measurements

 Core
 Finishing Coating production
 costs & time costs rate

 Correlation: 9 = High, 3 = Medium,
 1 = Low, Blank = No

Customer Requirements 3 4 5

 1 Reduce casting finishing 9
 costs
 2 Reduce the raw material 9
 cost of cores
 3 Reduce casting defects 9
 4 Increase speed of core 9 9
 production
 5 Reduce wastage and waste 3 1 1
 costs
 6 Reduce core machine & 9
 tooling downtime
 7 Reduce EH&S Impact 3 1
 8 Increase rate and 1
 completeness of sand
 removal, post cast
 9
10
Technical Priorities
 Relative Importance 108 99 93
 Importance, % 13.5 12.4 11.6
 Rank 3 4 5
 Measurement units $ $ /hr

 Customer CTQs/Measurements

 Core scrap
 and waste Sand/sand
 mixed sand Binder & additive
 costs amine costs costs

 Correlation: 9 = High, 3 = Medium,
 1 = Low, Blank = No

Customer Requirements 6 7 8

 1 Reduce casting finishing 1
 costs
 2 Reduce the raw material 3 9 9
 cost of cores
 3 Reduce casting defects 1 1
 4 Increase speed of core 3
 production
 5 Reduce wastage and waste 9
 costs
 6 Reduce core machine & 3 1
 tooling downtime
 7 Reduce EH&S Impact 1
 8 Increase rate and 3
 completeness of sand
 removal, post cast
 9
10
Technical Priorities
 Relative Importance 85 59 50
 Importance, % 10.6 7.4 6.3
 Rank 6 7 8
 Measurement units %/$ $ $

 Customer CTQs/Measurements

 Injuries,
 complains and
 claims etc Decore time

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

Customer Requirements 9 10 Score

 1 Reduce casting finishing 3 155
 costs
 2 Reduce the raw material 1 155
 cost of cores
 3 Reduce casting defects 115
 4 Increase speed of core 110
 production
 5 Reduce wastage and waste 96
 costs
 6 Reduce core machine & 1 85
 tooling downtime
 7 Reduce EH&S Impact 9 45
 8 Increase rate and 9 39
 completeness of sand
 removal, post cast
 9
10
Technical Priorities
 Relative Importance 47 32 800.0
 Importance, % 5.9 4.0 100.0
 Rank 9 10
 Measurement units $ secs Totals

Fig. 2. QFD Level 2 correlates metalcaster CTQs
with PUCB core and coremaking properties.

 Importance to
 Customer CTQs/ Customers, 1,
 Measurements 3 or 5

[down arrow] 1 Finishing costs & time 5
[down arrow] 2 Casting scrap / 5
 inspection costs and
 time
[up arrow] 3 Core strengths quality 5
[up arrow] 4 Core production rate 5
[down arrow] 5 Core scrap and waste 3
 mixed sand costs
[down arrow] 6 Coating costs 5
[down arrow] 7 Binder & amine costs 5
[down arrow] 8 Decore time 3
[down arrow] 9 Injuries, complaints 3
 and claims etc
[down arrow] 10 Sand / sand additive 5
 costs

 Technical Priorities
 Relative Importance
 Importance, %
 Rank
 Measurement units

 Test Methods

 [up arrow] [up arrow]

 PUCB Core & Core Making
 Product Properties

 Casting Mixed
 Customer CTQs/ erosion sand
 Measurements resistance benchlife

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 1 2

[down arrow] 1 Finishing costs & time 9 9
[down arrow] 2 Casting scrap / 9 3
 inspection costs and
 time
[up arrow] 3 Core strengths quality 9 9
[up arrow] 4 Core production rate 1
[down arrow] 5 Core scrap and waste 1 9
 mixed sand costs
[down arrow] 6 Coating costs 3 1
[down arrow] 7 Binder & amine costs
[down arrow] 8 Decore time
[down arrow] 9 Injuries, complaints 1 1
 and claims etc
[down arrow] 10 Sand / sand additive
 costs

 Technical Priorities
 Relative Importance 156 145
 Importance, % 14.3 13.3
 Rank 1 2
 Measurement units %

 Test Methods Erosion Wedge Drop in
 Casting tensile with
 3hrs old
 mixed sand

 [up arrow] [up arrow]

 PUCB Core & Core Making
 Product Properties

 Core Casting
 Customer CTQs/ storage surface
 Measurements humidity finish
 resistance

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 3 4

[down arrow] 1 Finishing costs & time 9 9
[down arrow] 2 Casting scrap / 3 9
 inspection costs and
 time
[up arrow] 3 Core strengths quality 9 3
[up arrow] 4 Core production rate 1
[down arrow] 5 Core scrap and waste 9 1
 mixed sand costs
[down arrow] 6 Coating costs 1 3
[down arrow] 7 Binder & amine costs
[down arrow] 8 Decore time
[down arrow] 9 Injuries, complaints 1 1
 and claims etc
[down arrow] 10 Sand / sand additive
 costs

 Technical Priorities
 Relative Importance 145 126
 Importance, % 13.3 11.5
 Rank 2 4
 Measurement units %

 Test Methods Tensile Surface
 stored 24hrs finish
 @ 90%RH casting

 [down arrow] [up arrow]

 PUCB Core & Core Making
 Product Properties

 Core Core strength
 Customer CTQs/ sticking
 Measurements and tooling
 resin
 wipe-off

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 5 6

[down arrow] 1 Finishing costs & time 3 3
[down arrow] 2 Casting scrap / 3 3
 inspection costs and
 time
[up arrow] 3 Core strengths quality 3 9
[up arrow] 4 Core production rate 9 3
[down arrow] 5 Core scrap and waste 9 3
 mixed sand costs
[down arrow] 6 Coating costs 1 1
[down arrow] 7 Binder & amine costs
[down arrow] 8 Decore time
[down arrow] 9 Injuries, complaints 1
 and claims etc
[down arrow] 10 Sand / sand additive 1
 costs

 Technical Priorities
 Relative Importance 125 109
 Importance, % 11.4 10.0
 Rank 5 6
 Measurement units psi/gm psi

 Test Methods Release and Tensile &
 resin Transverse
 wipe-off
 test

 [down arrow] [down arrow]

 PUCB Core & Core Making
 Product Properties

 Amine
 Casting consumption/
 Customer CTQs/ veiring/ core curing
 Measurements penetration times

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 7 8

[down arrow] 1 Finishing costs & time 9
[down arrow] 2 Casting scrap / 9 1
 inspection costs and
 time
[up arrow] 3 Core strengths quality 3
[up arrow] 4 Core production rate 9
[down arrow] 5 Core scrap and waste 3
 mixed sand costs
[down arrow] 6 Coating costs
[down arrow] 7 Binder & amine costs 3
[down arrow] 8 Decore time
[down arrow] 9 Injuries, complaints 1 1
 and claims etc
[down arrow] 10 Sand / sand additive
 costs

 Technical Priorities
 Relative Importance 93 92
 Importance, % 8.5 8.4
 Rank 7 8
 Measurement units %/sec

 Test Methods Penetration Amine
 casting consumption
 & curing
 efficiency
 test

 [down arrow] [down arrow]

 PUCB Core & Core Making
 Product Properties

 Customer CTQs/ Casting Core
 Measurements warpage shake-out
 time posts
 casting

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 9 10

[down arrow] 1 Finishing costs & time
[down arrow] 2 Casting scrap / 9
 inspection costs and
 time
[up arrow] 3 Core strengths quality 3
[up arrow] 4 Core production rate
[down arrow] 5 Core scrap and waste
 mixed sand costs
[down arrow] 6 Coating costs
[down arrow] 7 Binder & amine costs 3
[down arrow] 8 Decore time 9
[down arrow] 9 Injuries, complaints
 and claims etc
[down arrow] 10 Sand / sand additive
 costs

 Technical Priorities
 Relative Importance 60 42
 Importance, % 5.5 3.8
 Rank 9 10
 Measurement units in %

 Test Methods Warage block Shake-out
 casting casting

 Customer CTQs/
 Measurements Score

[down arrow] 1 Finishing costs & time 255
[down arrow] 2 Casting scrap / 245
 inspection costs and
 time
[up arrow] 3 Core strengths quality 240
[up arrow] 4 Core production rate 115
[down arrow] 5 Core scrap and waste 105
 mixed sand costs
[down arrow] 6 Coating costs 50
[down arrow] 7 Binder & amine costs 30
[down arrow] 8 Decore time 27
[down arrow] 9 Injuries, complaints 21
 and claims etc
[down arrow] 10 Sand / sand additive 5
 costs

 Technical Priorities
 Relative Importance 1093.0
 Importance, % 100.0
 Rank
 Measurement units Totals

 Test Methods

Fig. 3. QFD Level 3 shows the relationship between
PUCB core and coremaking properties and the
materials used to make the core/mold.

 Importance to
 PUCB Core & Core Customers, 1,
 Making Product Propert 3 or 5

[up arrow] 1 Core strength 5
[up arrow] 2 Casting surface 5
 finish
[up arrow] 3 Mixed sand benchlife 3
[down arrow] 4 Core sticking and 5
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion 5
 resistance
[up arrow] 6 Core storage humidity 3
 resistance
[down arrow] 7 Casting seining / 5
 penetration
[down arrow] 8 Amine consumption / 3
 core curing times
[down arrow] 9 Core shakeout timex 3
 core curing times
[down arrow] 10 Casting warp age 5

 Technical Priorities
 Relative Importance
 Importance, %
 Rank
 Measurement units

 Core Raw Materials

 Sand source/ Solvents
 quality

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No
 PUCB Core & Core
 Making Product Propert 1 2

[up arrow] 1 Core strength 9 9
[up arrow] 2 Casting surface 9 3
 finish
[up arrow] 3 Mixed sand benchlife 9 9
[down arrow] 4 Core sticking and 3 9
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion 3 1
 resistance
[up arrow] 6 Core storage humidity 3 9
 resistance
[down arrow] 7 Casting seining / 9
 penetration
[down arrow] 8 Amine consumption / 1 9
 core curing times
[down arrow] 9 Core shakeout timex 3 3
 core curing times
[down arrow] 10 Casting warp age 3 1

 Technical Priorities
 Relative Importance 228 205
 Importance, % 21.2 19.1
 Rank 1 2
 Measurement units

 Core Raw Materials

 Sand PU polymer
 additives

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 PUCB Core & Core
 Making Product Propert 3 4

[up arrow] 1 Core strength 9 9
[up arrow] 2 Casting surface 9 3
 finish
[up arrow] 3 Mixed sand benchlife 9 9
[down arrow] 4 Core sticking and 3 3
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion 3 3
 resistance
[up arrow] 6 Core storage humidity 1 1
 resistance
[down arrow] 7 Casting seining / 9
 penetration
[down arrow] 8 Amine consumption / 1 3
 core curing times
[down arrow] 9 Core shakeout timex 1 3
 core curing times
[down arrow] 10 Casting warp age 3

 Technical Priorities
 Relative Importance 201 153
 Importance, % 18.7 14.2
 Rank 3 4
 Measurement units

 Core Raw Materials

 Resin Coating
 additives refractory

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 PUCB Core & Core
 Making Product Propert 5 6

[up arrow] 1 Core strength 3
[up arrow] 2 Casting surface 1 9
 finish
[up arrow] 3 Mixed sand benchlife 9
[down arrow] 4 Core sticking and 9
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion 9
 resistance
[up arrow] 6 Core storage humidity 9
 resistance
[down arrow] 7 Casting seining / 1
 penetration
[down arrow] 8 Amine consumption / 3
 core curing times
[down arrow] 9 Core shakeout timex 3
 core curing times
[down arrow] 10 Casting warp age

 Technical Priorities
 Relative Importance 137 95
 Importance, % 12.7 8.8
 Rank 5 6
 Measurement units

 Core Raw Materials

 Coating Amine type
 solvent

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 PUCB Core & Core
 Making Product Propert 7 8

[up arrow] 1 Core strength 1 1
[up arrow] 2 Casting surface
 finish
[up arrow] 3 Mixed sand benchlife 3
[down arrow] 4 Core sticking and
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion 1
 resistance
[up arrow] 6 Core storage humidity 9 1
 resistance
[down arrow] 7 Casting seining /
 penetration
[down arrow] 8 Amine consumption / 1
 core curing times
[down arrow] 9 Core shakeout timex
 core curing times
[down arrow] 10 Casting warp age

 Technical Priorities
 Relative Importance 37 20
 Importance, % 3.4 1.9
 Rank 7 8
 Measurement units

 Core Raw Materials

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No

 PUCB Core & Core
 Making Product Propert 9 10

[up arrow] 1 Core strength
[up arrow] 2 Casting surface
 finish
[up arrow] 3 Mixed sand benchlife
[down arrow] 4 Core sticking and
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion
 resistance
[up arrow] 6 Core storage humidity
 resistance
[down arrow] 7 Casting seining /
 penetration
[down arrow] 8 Amine consumption /
 core curing times
[down arrow] 9 Core shakeout timex
 core curing times
[down arrow] 10 Casting warp age

 Technical Priorities
 Relative Importance
 Importance, %
 Rank
 Measurement units

 PUCB Core & Core
 Making Product Propert Score

[up arrow] 1 Core strength 205
[up arrow] 2 Casting surface 170
 finish
[up arrow] 3 Mixed sand benchlife 144
[down arrow] 4 Core sticking and 135
 tooling resin
 wipe-off
[up arrow] 5 Casting erosion 100
 resistance
[up arrow] 6 Core storage humidity 99
 resistance
[down arrow] 7 Casting seining / 95
 penetration
[down arrow] 8 Amine consumption / 54
 core curing times
[down arrow] 9 Core shakeout timex 39
 core curing times
[down arrow] 10 Casting warp age 35

 Technical Priorities
 Relative Importance 1076.0
 Importance, % 100.0
 Rank
 Measurement units Totals

Fig. 4. QFD Level 4 considers the interactions of
coremaking process controls with PUCB core and
coremaking properties.

 PUCB Core & Core Importance to
 Making Product Customers, 1,
 Properti 3 or 5

[up arrow] 1 Core strength 5
[down arrow] 2 Core sticking and 5
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 3
[up arrow] 4 Casting surface finish 5
[up arrow] 5 Core storage humidity 3
 resistance
[down arrow] 6 Amine consumption / 3
 core curing times
[up arrow] 7 Casting erosion 5
 resistance
[down arrow] 8 Core shake-out time 3
 post casting
[down arrow] 9 Casting warpage 5
[down arrow] 10 Casting wining / 5
 penetration

 Technical Priorities
 Relative Importance
 Importance, %
 Rank
 Measurement units

 [down arrow] [up arrow]

 Core Making Process Controls

 Resin Air
 addition quality
 (dryness)

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No
 PUCB Core & Core
 Making Product
 Properti 1 2

[up arrow] 1 Core strength 9 9
[down arrow] 2 Core sticking and 9 3
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 1 9
[up arrow] 4 Casting surface finish 9 3
[up arrow] 5 Core storage humidity 3 9
 resistance
[down arrow] 6 Amine consumption /
 core curing times
[up arrow] 7 Casting erosion 3
 resistance
[down arrow] 8 Core shake-out time 9
 post casting
[down arrow] 9 Casting warpage
[down arrow] 10 Casting wining /
 penetration

 Technical Priorities
 Relative Importance 189 129
 Importance, % 24.0 16.3
 Rank 1 2
 Measurement units

 Core Making Process Controls

 Location Good tooling
 (ambient design
 temperature/
 humidity)

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No
 PUCB Core & Core
 Making Product
 Properti 3 4

[up arrow] 1 Core strength 3 3
[down arrow] 2 Core sticking and 3 9
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 9
[up arrow] 4 Casting surface finish 1 3
[up arrow] 5 Core storage humidity 9
 resistance
[down arrow] 6 Amine consumption / 9
 core curing times
[up arrow] 7 Casting erosion 3
 resistance
[down arrow] 8 Core shake-out time
 post casting
[down arrow] 9 Casting warpage
[down arrow] 10 Casting wining /
 penetration

 Technical Priorities
 Relative Importance 104 102
 Importance, % 13.2 12.9
 Rank 3 4
 Measurement units

 [up arrow]

 Core Making Process Controls

 Mixed sand Good gas &
 flowability purge
 settings and
 venting

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No
 PUCB Core & Core
 Making Product
 Properti 5 6

[up arrow] 1 Core strength 9 3
[down arrow] 2 Core sticking and 3
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 3
[up arrow] 4 Casting surface finish 3
[up arrow] 5 Core storage humidity 3
 resistance
[down arrow] 6 Amine consumption / 9
 core curing times
[up arrow] 7 Casting erosion 1
 resistance
[down arrow] 8 Core shake-out time
 post casting
[down arrow] 9 Casting warpage
[down arrow] 10 Casting wining /
 penetration

 Technical Priorities
 Relative Importance 89 51
 Importance, % 11.3 6.5
 Rank 5 6
 Measurement units

 [down arrow] [down arrow]

 Core Making Process Controls

 Blow pressure Sand
 temperature

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No
 PUCB Core & Core
 Making Product
 Properti 7 8

[up arrow] 1 Core strength 1 3
[down arrow] 2 Core sticking and 9
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 9
[up arrow] 4 Casting surface finish
[up arrow] 5 Core storage humidity
 resistance
[down arrow] 6 Amine consumption /
 core curing times
[up arrow] 7 Casting erosion
 resistance
[down arrow] 8 Core shake-out time
 post casting
[down arrow] 9 Casting warpage
[down arrow] 10 Casting wining /
 penetration

 Technical Priorities
 Relative Importance 50 42
 Importance, % 6.3 5.3
 Rank 7 8
 Measurement units

 [down arrow]

 Core Making Process Controls

 Operator
 training/
 experience

 Correlation: 9 = High,
 3 = Medium, 1 = Low,
 Blank = No
 PUCB Core & Core
 Making Product
 Properti 9 10

[up arrow] 1 Core strength 3
[down arrow] 2 Core sticking and
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 3
[up arrow] 4 Casting surface finish
[up arrow] 5 Core storage humidity
 resistance
[down arrow] 6 Amine consumption / 3
 core curing times
[up arrow] 7 Casting erosion
 resistance
[down arrow] 8 Core shake-out time
 post casting
[down arrow] 9 Casting warpage
[down arrow] 10 Casting wining /
 penetration

 Technical Priorities
 Relative Importance 33
 Importance, % 4.2
 Rank 9
 Measurement units

 PUCB Core & Core
 Making Product
 Properti Score

[up arrow] 1 Core strength 215
[down arrow] 2 Core sticking and 180
 tooling resin wipe-off
[up arrow] 3 Mixed sand benchlife 102
[up arrow] 4 Casting surface finish 95
[up arrow] 5 Core storage humidity 72
 resistance
[down arrow] 6 Amine consumption / 63
 core curing times
[up arrow] 7 Casting erosion 35
 resistance
[down arrow] 8 Core shake-out time 27
 post casting
[down arrow] 9 Casting warpage
[down arrow] 10 Casting wining /
 penetration

 Technical Priorities
 Relative Importance 789.0
 Importance, % 100.0
 Rank
 Measurement units Totals
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Copyright 2007, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
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Author:Wang, X.
Publication:Modern Casting
Date:Mar 1, 2007
Words:5004
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