Simulation - Cure all for beleagured engineering enterprises?

In these days of economic challenges, companies are forced to look at ways and means of reducing costs to survive and stay profitable. Some of the immediate priorities that need urgent management focus include:

1. How to reduce product cost to sustain healthy margins?
2. How to innovate and deliver products of high value without compromising on safety?
3. How to increase an already shrinking market share?
4. How to eliminate warranty costs, product recall and re-work?

The questions are unending. This is just a partial list. The answers just do not seem to be there.

A careful analysis of all the questions, posed above, provides a common denominator - Design

Product cost is dictated by the Bill of Materials and Drawings. Innovation and USP of a product is driven by product function and efficiencies. Increasing market share is directly related to selling better products of higher value at affordable (read not lower) cost. Warranty issues, recall and re-work relate to product not functioning as intended. All these lead to one common cause - Design, provided the product has been manufactured to specifications provided.

It is well known, without contention, that upto 85% of product cost is influenced by design. Then it would be prudent, on the part of every company that is looking at ways and means to stay profitable, to scrutinize the design process and revisit existing designs to achieve higher levels of efficiency, profitability and success.

If the design teams were to be able to arrive at innovative designs by evaluating a variety of design concepts, validating the same using simulation tools, optimizing designs for least cost and releasing drawings incorporating functional tolerances that meet intended functions, the challenges mentioned in the beginning of this article get addressed with higher levels of reliability, confidence and perfection.

Simulation tools in design are of 3 types. They are:

• Finite Element Analysis & Fluid Flow computations
• Kinematic Analysis for Mechanisms
• Tolerance Analysis for Stack-up calculations - Synthesis and Analysis of Tolerancing strategies for cost-effective design

CAD Integrated FE analysis and CFD computations are commonplace these days. In addition to overcoming the data translation issues found with standalone simulation tools, optimization of designs based on parametric CAD dimensions as design variables provides the design engineer with a rich set of options to quickly arrive at functional, failsafe designs.

Shaft Failure - Case Study of Warranty Problem

Above is a case study of a shaft failure, done using SolidWorks Simulation, that could have been avoided if a simple life calculation had been performed. Not only is it expensive to replace during warranty period, but time and efforts spent in getting it identified and corrected, leads to unplanned expenditure. Needless to say the company image takes a beating where the damages are incalculable.

Another example of a design gone wrong is shown below.

Case study of a Product Recall

Failure due to improper calculation of loads and stresses lead to a correction on the plastic mould. The product was re-designed for better strength, as shown in the SolidWorks Simulation design above, with a higher factor of safety. The product recall costs are staggering in addition to creation of a huge pile of inventory of parts that cannot be re-used.

Efficiency of a cyclone separator was drastically improved, at the design stage, by performing integrated CFD, as shown below in the FloWorks model. By validating early in the design process, a near-optimal cost effective design was possible for chosen configuration. Particle tracking helped understand bottlenecks such as re-circulation in addition to pressure drop calculations.

Case Study of Optimal Design: Flow Simulation of a Cyclone separator

Innovative Designs can lead to creation of a new market for products that have never been explored. In addition to creating a market share, sans competition, it helps leverage better sales for companies, resulting in increased profits.

Tolerance Analysis can help save money for any manufacturing engineering enterprise by allocating required tolerance to meet design function while minimizing costs.
Tolerance Stack-up Analysis/ Synthesis using SigmundWorks inside SolidWorks

Benefits of Simulation are many-fold. Some of the important ones are:

• Do it Once – Do it Right
• Give the Best to the Organization
• Profit on Day One of Product Launch
• Valuefacture – Eliminates Competition
• Save our Planet

GD & T - Power of Feature Control Frames using SolidWorks

Feature Control Frame forms the heart of the Geometric Dimensioning and Tolerancing ( GD & T ) practice for engineers involved in creating, manufacturing and inspecting designs. In fact it is the greatest invention of engineering expressions in symbolic language that it is finding unilateral acceptance by the engineering community as a whole.

For the un-initiated, let us considere a hole dimensioned as follows:
Read from left to right, the Feature Control Frame states that "Position of the Axis of a pattern of 8 holes when produced within stated size limits, can be off-centre within a diametral tolerance zone of 0.50 when produced at Maximum Material Condition, when the part is located on Datum A as Primary, Datum Feature of Size B when produced at Maximum Material Condition as Secondary and Datum C as Tertiary references."

Feature Control Frames have a characteristic symbol in the first cell, a tolerance value with a zone descriptor and material modifier (if any) as the second cell followed by cells having Datum references ranging from 1 to 3 depending on the design specification that the tolerance definition is intended to convey. Number of datums depend and possible material modifiers (on datum features of sizes) depends on the intention and feature that is controlled.

Many a times, design intent and design specifications are wrongly used interchangeably while producing drawings. GD & T Drawing is intended to convey design specifications in an unambiguous manner and not the design intent. Sounds strange? Read again !

GD & T symbols, when used with care and purpose, have been proven to reduce costs and greatly improve quality while ensuring part interchangeability and protecting the parts' intended fit, form and functions.

SolidWorks helps designers achieve a great level of definition control with GD & T using DimXpert. Even Imported geometries can have the complete Dimensional schematic completed in no time with accurate representation of the design specifications.

Feature Control Frame Definition using DimXpert

User specified Datums with selected order of precedence alongside features of sizes can be defined for various levels of control based on size, form, orientation and location. Features defined using feature control frame are ascertained for completeness of definition. Features shown as green are complete in dimensional definition. If the feature selected is a part of a pattern of features, say a hole pattern, then a common reference frame with necessary number of features are provided automatically.

Using SolidWorks, this is possible even in the case of imported geometries as shown. This approach enhances accuracy and adequacy, when dimensioning a part with a huge history of features requiring dimensioning.

When a circular feature of size, such as Datum B shown in the Figure, is selected as a datum for another feature, the feature dimensioning is automatically defined in all aspects with appropriate Feature control frame (in this case Perpendicularity) in context to the datum feature used (in this case Datum A) in precedence. This approach, not only saves time, but also ensures dimensional completeness thereby preventing ambiguity in manufacturing and inspection downstream during part manufacture.

Hole depth is also indicated in the Feature Control Frame while defining size limits. Tolerances specified as based on default values specified by the user that can be modified based on cost and practical manufacturing considerations (including machine Cp and Cpk).

When multiple features refer to the same Datum, this is automatically recognized by SolidWorks and common Datum sequence is followed in all relevant Feature Control Frames, signifying a single setting during manufacture and inspection.

In summary, DimXpert inside SolidWorks reduces effort required to develop GD & T drawings while improving accuracy of representation and completeness in definition. This eliminates ambiguity, resulting in overall cost and time savings.

Overcoming Market Challenges - A Design Approach

Recessionary trends in markets always force customers to re-think before spending and postpone high-value investment decisions. In these days of wild economic oscillations, every company involved in manufacturing and marketing of products is faced with the following scenarios:

1. Reduced Orders for Products
2. Shrinking profit margin
3. Competitive pricing from predatory products

Add to these challenges, the burdening effects of increased input raw material costs, extended product development time and costly re-work due to failures, we have a problem of monstrous proportions that affects the company bottom-line and survivability.

In order to stay competitive, increase market-share and provide more value for less money, product development companies need to do three things:

1. Innovate
2. Improvise
3. Implement

It is well known that 80%-85% of a product cost is driven/ decided by Design. Input raw-material, number and sequence manufacturing operations, product testing, product/ design re-work, field failure correction, enhancing product performance, improving efficiency all have their main input from Design. No time is better time than NOW to revisit our Designs and see how we can address Critical Business Issues.

Cost Reduction Exercise should be done in a conscious and time-bound manner to have any effect. Simple steps, when followed with due diligence, can turn around companies towards higher growth path and profitability. History is replete with testimonies to this cause. 'Jelly-bean' type rounded shape of Ford Taurus increased sales and profitability for Ford Motor Company in the mid-eighties on account of the three 'I's mentioned above.

Step I: Set Goals

Goal setting is an important process that determines the success rate of the exercise. Such goals should have clear alignment with Critical Business Issues facing the company. For example, let us say, a Company ABC that has had a successful run with one of their mainstream products is facing competition from an overseas Company in terms of price. The Goal could be:

Increase Overall Profit margin by 5% while addressing the following:

1. Reduce finished product cost by 10%
2. Integrate new features that lowers overall cost of ownership to end-consumer by 10%
3. Implement within 1 month

Goal Setting in terms of tangible benefits within specified time-line helps in more ways than one: Events Force Action

Step II: Design Action Plan

Design Team, identified to achieve stated goals, then needs to work on a definitive Action Plan with an accepted mission statement: 'Failure is not an Option'

Steps involved in the Action Plan could have following indicators:

• Reduce Number of Parts going into an Assembly (by integration, elimination or augmenting product functions)
• Reduce Manufacturing Operations required to produce a part (by simplifying geometry)
• Reducing number of serviceable parts (thereby reducing service parts inventory)
• Revisit Bill of Materials to standardize on parts (replace parts with Standard Catalog parts where permitted)
• Reduce fasteners and/ or standard parts to minimum required quantities
• Minimize product configurations to achieve modular variants
• Evaluate Power-to-Weight Ratio for optimal utilization
• Check tolerances of parts going into assemblies and perform tolerance stack-up calculations to reduce/ eliminate rejections at part/ assembly levels
• Validate Designs for Fit, Form and Functional aspects with emphasis on least cost
• Ask Questions such as: Why, Why-not, How, When and What for every design feature that adds to overall cost

Step III: Perform Fit, Form and Functional Validation

Revisiting every design to have a better understanding, in terms of cost is bound to be a profitable exercise. However, for proven products, the inertia to change or the fear of 'tinkering' with a working design over-powers the incentive to adopt new technologies and processes that result in a final product having the least cost and best functionality in its range. This 'fear' or 'reluctance' can be avoided or confronted ( based on the company's approach) by Validating every aspect of Design in terms of their Fit, Form and Function. This provides a basis for the engineering evolution of the product and helps revisit equations in a changed economic scenario.

Step IV: Implement

By adhering to the action plan that helps reach goals within stipulated time frame, cost reduction end benefits are assured. The will to implement after overcoming the fear of change has to be a pre-requisite to the conduct of this exercise. By re-visiting the goals and seeing how close or how far the benefits are, it helps set clear targets for further re-assessments that help build a competitive product.

None of the above would help succeed without the Team taking the ownership for the success or the not-so-successful exercise of competitive product development.

In bleak market scenarios, this exercise provides more benefits even to other areas of an Enterprise:

1. Redefining Value and Enhancing Customer Satisfaction
2. Confidence in Product Performance and Augmented USP
3. Pride of Ownership for a Superior Product

All the above go a long way in instilling a higher level of resolve to face competition, enhance value and reduce the overall cost of ownership for Customers and Prospects alike.

Notwithstanding other exercises, Design Re-validation is a Necessity that protects the bottom line while ensuring higher profitability for Product Development companies.