Executive answer
Carry the quantity and its boundary into the work record
- Record the actual quantity: N is force, N/mm is line load, and Pa or MPa is pressure.
- The same total force can produce different line loads when the effective width changes; pressure still needs contact area.
- A comparable numerical setting is only one part of a controlled mounting process, not a bond-quality result.
Current guidance context
What OEM engineers and sourcing teams should compare
An assembly instruction can say 'use the same roller pressure' while the accompanying record contains only a force value. That leaves the next site to decide what 'same' means. Has the roller changed width? Is the number a normal load at the contact or a setting elsewhere on the machine? Which adhesive lands receive the pass?
The useful handoff is a quantity-and-boundary record. It lets the receiving team preserve the intended control or identify a change requiring review. It does not establish a universal pressure for membrane switches. The worked cases below expose the missing inputs without prescribing how hard to press a panel.
Separate force, line load and pressure
NIST lists the kilogram as a unit of mass, the newton as a unit of force and the pascal as a newton per square meter. For this worksheet, F denotes the total normal force transmitted through the defined contact. Dividing F by an effective loaded width w gives a line load, q = F/w. Dividing F by a contact area A gives its area-average normal pressure, p = F/A.
These expressions need different geometry. N/mm does not mean N/mm². Because one square millimeter is one millionth of a square meter, 1 N/mm² equals 1 MPa. A mass label such as kilograms also cannot be relabeled as pressure: it does not specify the resulting force at the interface or the area over which that force acts.
Keep a machine's control location in the record. A pneumatic pressure setting, a handle-force reading and a normal load at the roller contact name different boundaries. A verified machine-and-fixture relationship may connect them, but the shared word pressure does not. This guide supplies no machine conversion or operating instruction.
Read adhesive guidance with its original quantity
3M's adhesive-selection guidance for applications including membrane switches identifies applied pressure as part of establishing adhesive-to-surface contact. That supports retaining the mounting process with the material and substrate record. It does not supply a universal force, pressure or conditioning requirement for an HYR assembly.
As a bounded terminology example, 3M Australia's VHB application page discusses both a roll-down force and pressure at the tape bond line, using different units. They are not interchangeable labels. Do not copy a number from one field into the other, or treat guidance for that tape family as approval of a membrane-switch adhesive and construction.
Work a tool change without inventing contact area
Hypothetical HYR editorial arithmetic only: suppose a total normal load of 60 N is transmitted through a defined strip with no other load path. Case A has an effective loaded width of 30 mm. Case B has 60 mm. The respective line loads are 60/30 = 2 N/mm and 60/60 = 1 N/mm. Keeping total force has not kept line load.
Contact area is still missing. To illustrate its separate role, assume a rectangular footprint extending 2 mm in the rolling direction in each case. These are invented dimensions, not measured roller contacts or a deformation model. A then has 30 × 2 = 60 mm² and p = 60/60 = 1 MPa. B has 60 × 2 = 120 mm² and p = 60/120 = 0.5 MPa.
In case C, retain B's 60 N and 60 mm width but assume a 4 mm contact length. The line load remains 1 N/mm. The assumed area becomes 240 mm² and the average pressure becomes 0.25 MPa. Thus even a matching line load does not identify pressure when contact area is unknown.
The table's arithmetic is reproducible; the assumed footprints are not evidence. Do not infer them from a roller's nominal diameter, a front-view photograph or the panel's overall dimensions. Nor does F/A establish that every point experiences that average. Real contact distribution and any other load paths require applicable evidence before a process-equivalence conclusion.
Carry the loaded land and pass map into the record
On a membrane-switch assembly drawing, distinguish the panel outline from the adhesive lands and the instantaneous loaded region. A roller may pass over a border, an opening or a supported feature; the whole panel area is not automatically the area carrying its load at that moment. Define the reviewed region and support before assigning a denominator.
Keep tool identity and condition, effective width, normal-load measurement, housing support and the planned route together. Record speed and pass count separately rather than using either as a substitute for load. Identify window, key and tail-transition regions that need a specific support or exclusion decision from the responsible assembly team.
If the new tool cannot reproduce the intended route or support, record the change instead of claiming equivalence from a matching display value. Retain the actual adhesive, housing finish, preparation and conditioning instructions too. Those questions belong to the material-and-assembly qualification, not to the unit conversion.
Catch five process-record failures before transfer
These are hypothetical document-review gaps, not observed HYR defects or customer cases. Resolve the missing field before deciding whether a changed process is acceptable.
- Mass called pressure: a tool is identified only by kilograms. Recover the intended load definition, application boundary and method instead of appending a pressure unit.
- Width lost during transfer: a replacement roller retains the total force but changes the effective loaded width. Recalculate the line-load field and obtain a documented disposition.
- Contact area invented: the full panel area or an assumed strip is used as if it were a measured roller footprint. Preserve the assumption and keep actual pressure unverified.
- Matching setpoint, different boundary: a machine setting is compared with an interface load. Obtain the applicable machine/fixture relationship rather than equating the numbers.
- A numerical match called a bond pass: load is recorded but coverage, preparation, conditioning and the mounted inspection are absent. Complete the agreed evidence instead of releasing from the setting alone.
Release a comparable mounting record with the RFQ
Use a short transfer sheet with four linked blocks: the controlled material and assembly; the tool and load boundary; the geometry, support and pass record; and the agreed inspection result. Label each field as specified, measured, calculated, assumed or unknown. That prevents a calculated average from acquiring the status of a measurement as the record passes between teams.
Before approval, ask whether the receiving setup preserves the intended quantity, whether its measurement is valid at the named boundary, and whether the actual assembly completed the project-selected checks. A peel report has its own specimen, units and procedure; it is not a pressure calibration. Sealing and key function also remain separate acceptance questions.
For an HYR review, share the available controlled drawing and nonconfidential mounting record through the secure engineering RFQ. Mark the proposed tool or process change and the missing evidence. This can clarify quotation and sample-review inputs; it does not promise a pressure target, testing service, bond result, price or delivery date.