Define the wet-end objective
State whether the priority is first-pass retention, ash retention, drainage, white-water solids, saveall loading or a balanced improvement. Include the current machine limitation and grade target.
Retention and drainage are connected but not interchangeable. A product that maximizes one result can create oversized floc, poor formation or unstable press behavior.
Characterize the furnish
Record fiber source, fines, filler type and loading, broke, conductivity, pH, temperature, anionic demand and major wet-end additives. Include normal and upset ranges.
CPAM response changes with furnish charge, dissolved and colloidal material, closure and shear. A generic grade recommendation cannot replace representative stock testing.
Screen charge and molecular profile
Compare a bounded set of cationic charge and molecular profiles at equal active dose. Use the incumbent and untreated stock as controls.
Higher charge or molecular weight is not automatically better. Adsorption, bridging, floc size and shear recovery must fit the paper machine.
Reproduce addition and shear
Add the candidate at the planned stock consistency and process location, then apply the actual sequence and a representative shear history before drainage and retention measurement.
A quiet beaker screen can overstate performance because fan-pump, pressure-screen and headbox shear alter floc structure.
Measure the complete sheet response
Track total and ash first-pass retention, drainage or freeness, white-water solids and turbidity, formation, sheet strength and machine cleanliness as applicable.
Approve a stable operating window rather than the single highest retention point. Formation and quality remain release criteria.
Preserve the tested identity
Connect the approved sample code to preparation instructions, COA, SDS, packaging, storage, quotation and receiving checks.
Requalify after meaningful furnish, filler, wet-end chemistry, addition-point, machine-speed or product-identity changes.