The 3M ASPEC Method: A 5-Step Guide to Product Selection
The 3M ASPEC method provides a comprehensive, structured approach to selecting the optimal industrial adhesive or tape. By methodically addressing these five core criteria, engineers can ensure the final product choice meets all performance, production, and cost requirements.
Step 1: A – Assembly (Define the Joint)
The initial step focuses on the physical characteristics and geometry of the joint. The type of joint dictates the required mechanical properties of the bond (e.g., strength in shear, peel, or tension) and the necessary form of the adhesive (liquid, film, or tape).
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Consideration |
Key Questions |
Selection Impact |
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Joint Type |
Is it a lap joint, butt joint, or T-joint? Is it a laminating (large surface) or small joint assembly? |
Determines the required stress distribution. Lap joints favour high shear strength (structural adhesives), while T-joints need high peel strength (flexible tapes/adhesives). |
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Component Size |
What is the size and thickness of the components being bonded? |
Thicker or larger components may be better suited for liquid adhesives, while uniform lamination favors tapes or film adhesives. |
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Dimensional Gap |
Is there a gap between the substrates? If so, what is the gap size? |
Dictates the need for void fillers or thicker, gap-filling adhesives (e.g., specific two-part epoxies). |
Step 2: S – Substrate (Analyse the Materials)
This step assesses the materials being bonded, as their chemical nature and surface condition directly influence adhesion.
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Consideration |
Key Questions |
Selection Impact |
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Material Type |
Are you bonding similar (e.g., steel to steel) or dissimilar (e.g., metal to plastic) materials? |
Dissimilar materials often require more flexible adhesives (Urethanes) to compensate for different thermal expansion rates and prevent galvanic corrosion. |
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Surface Energy |
Is the material High Surface Energy (HSE) like metal/glass, or Low Surface Energy (LSE) like polyolefin plastics (PE/PP)? |
LSE plastics are hard to bond and require specialised Acrylic adhesives or surface preparation (primers/treatments). |
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Surface Condition |
Is the surface clean, smooth, porous, textured, or contaminated (oil, dust, powder coat)? |
Heavily contaminated or textured surfaces may require dedicated surface preparation or the use of specific high-tack VHB™ Tapes. |
Step 3: P – Process (Optimise Manufacturing)
The process step defines how the product will be assembled and the necessary speed of the manufacturing line. This is key to selecting the correct product format and cure mechanism.
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Consideration |
Key Questions |
Selection Impact |
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Speed/Throughput |
How quickly must the component reach handling strength (the time before it can be moved)? |
Tapes or Instant Adhesives offer fast/immediate handling strength. Epoxies and Urethanes often require fixturing/cure time. |
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Application Method |
Will the adhesive be applied manually (cartridge/hand roller) or via automation (robotic dispensing)? |
Liquid adhesives allow for automated precision dispensing. Tapes are ideal for automated die-cutting and placement. |
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Safety & Regulation |
Are there regulatory concerns regarding flammability, odour, or VOCs (Volatile Organic Compounds) in the work environment? |
May necessitate the use of low-odour acrylics or water-based/solvent-free alternatives. |
Step 4: E – End Use (Environmental Durability)
This step addresses the environmental conditions the final product will endure, ensuring the bond remains intact throughout the product's lifespan.
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Consideration |
Key Questions |
Selection Impact |
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Temperature |
What is the minimum and maximum operating temperature of the assembly? |
High temperatures require high-performance, heat-resistant Epoxies. Extreme low temperatures require adhesives that maintain flexibility. |
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Chemical Exposure |
Will the product be exposed to moisture, oils, solvents, or cleaning chemicals? |
Dictates the required chemical resistance. Epoxies generally offer superior resistance to harsh solvents and chemicals. |
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Environmental Stress |
Will the joint be exposed to UV light, excessive vibration, or significant cyclical stress (fatigue)? |
UV exposure necessitates UV-stable products. High vibration demands flexible, damping adhesives (Urethanes or VHB™ Tapes). |
Step 5: C – Cost (Analyse Total Applied Cost)
The final step shifts focus from unit price to the Total Applied Cost, evaluating the overall economic efficiency gained by using adhesives or tapes.
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Consideration |
Key Questions |
Selection Impact |
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Labour and Rework |
Does the adhesive eliminate costly steps like grinding, drilling, or surface finishing? |
Choosing an adhesive that requires less surface prep (e.g., LSE Acrylics) or eliminates post-processing (no weld grinding) can drastically lower labour costs. |
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Material Usage |
Does the adhesive enable the use of lighter, thinner, or less expensive substrates? |
Adhesives prevent corrosion and allow for multi-material lightweighting, leading to long-term savings in material and shipping costs. |
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Capital Investment |
How does the cost of dispensing equipment compare to the cost of welding or riveting machinery? |
Lower capital investment in dispensing equipment can offset a higher unit cost for the adhesive itself. |
Partnering with Techsil
By completing the ASPEC process, you will have a clear, prioritised list of technical requirements. Our experts can now efficiently match these precise specifications to the ideal 3M Scotch-Weld adhesive, tape, or sealant solution, ensuring performance and cost-effectiveness.
Ready to move from specification to solution?