{"id":3830,"date":"2026-11-14T14:00:00","date_gmt":"2026-11-14T14:00:00","guid":{"rendered":"https:\/\/swesd.com\/?p=3830"},"modified":"2026-11-12T19:40:04","modified_gmt":"2026-11-12T19:40:04","slug":"understencil-cleaning-roll-usage-per-shift","status":"publish","type":"post","link":"https:\/\/swesd.com\/ja\/blog\/understencil-cleaning-roll-usage-per-shift\/","title":{"rendered":"Understencil Cleaning Roll Usage per Shift: A Planning Calculation"},"content":{"rendered":"

Estimate understencil cleaning roll usage per shift from the approved printer recipe, the number of cleaning events and the actual fresh web advance per event. Add documented setup, restart and threading losses, then compare the total length with usable stock. Do not divide the shift duration by an assumed roll life or borrow another printer’s paper feed setting. The estimate supports stores and purchasing; it does not justify reducing cleaning frequency. Keep the qualified printing and cleaning process unchanged while you learn how much material it consumes, and label every unmeasured input as an assumption.<\/p>\n

Define what one cleaning event means<\/h2>\n

A cleaning event is the complete approved sequence counted by your process record. It may contain several actions, and those actions may not all advance fresh web in the same way. Record the printer, program revision, selected roll and sequence before doing the arithmetic. A count of wipe strokes is not automatically a count of fresh-material advances, and a printer cycle is not automatically one finished PCB.<\/p>\n

Ask the process engineer or trained equipment owner which counter or report corresponds to the sequence. If a machine reports wet, dry and vacuum actions separately, confirm how those entries relate to the programmed event. Do not add them as three identical consumption events without checking the actual feed logic. A simple definition on the worksheet prevents a plausible-looking estimate from being wrong by a large factor.<\/p>\n

The SWESD stencil wiper product page<\/a> lists multiple roll configurations. The illustration here represents the white roll and extended core geometry in the product reference; it is not a scale drawing or a statement of usable length. Select the approved item before calculating stock. For the broader fit decision, use the SMT stencil wiper selection guide<\/a>.<\/p>\n

Collect the inputs without changing the process<\/h2>\n

Use the planned number of relevant print cycles, not just the factory’s shift length. Exclude planned downtime from any time-based production estimate and state how startup trials or reprints are treated. For mixed production, separate the jobs when their cleaning intervals or feed amounts differ. One blended number can hide the job that consumes most of the available material.<\/p>\n

Obtain the programmed cleaning interval and the approved fresh web advance. Confirm the unit and whether it represents a complete event or only one step. If the feed value is not available from controlled documentation, request a safe approved observation method. Do not place hands, a ruler or a mark on moving web inside an operating printer to make the measurement.<\/p>\n

Record nonproduction use separately: threading, setup trials, restarts, aborted jobs and material discarded because of damage. Keep recoverable unused stock separate from discarded length. If no reliable measurement exists for a loss, record the observation and use an explicitly provisional allowance. A rounded estimate with transparent limitations is more useful than a precise total built from guesses.<\/p>\n

\"Single
Single white stencil wiper roll with both extended core ends visible. Illustration based on the SWESD product reference; application suitability must be verified.<\/figcaption><\/figure>\n

Calculate planned consumption in one unit<\/h2>\n

For a simple repeating recipe, a conservative planning count can be written as E = ceil(P \/ I) + X. E is the number of cleaning events to budget, P is planned relevant print cycles, I is the approved interval in print cycles per event, and X is additional separately budgeted events. The ceiling rounds a fraction upward. This is a planning convention; the actual machine may start or end its sequence differently, so reconcile it with the printer’s counter logic.<\/p>\n

Total required length is L = E \u00d7 A + S. A is fresh web advance in meters per complete event, and S is separately recorded setup or discard length in meters. When a sequence uses different advances for different actions, calculate the complete event consumption from those actions first. Do not multiply the entire event by the number of strokes again if A already includes them.<\/p>\n

For an invented arithmetic example, assume P = 1,000 print cycles, I = 5 cycles per event, X = 10 extra events, A = 40 millimeters per event and S = 600 millimeters. Convert A to 0.040 meters and S to 0.600 meters. The planning count is 210 events, giving L = 210 \u00d7 0.040 + 0.600 = 9.000 meters. These are hypothetical inputs, not SWESD specifications, printer recommendations or a qualified cleaning recipe.<\/p>\n

Check the units before accepting the result. Millimeters and meters differ by a factor of one thousand. NIST’s SI unit guidance<\/a> is a suitable reference for consistent unit notation. Record conversions on the worksheet instead of relying on someone to remember whether the original feed entry was in millimeters, centimeters or inches.<\/p>\n

Convert required length into a stock decision<\/h2>\n

Use the approved usable length of the selected roll, not its outside diameter or a visual guess. Usable length may differ from nominal supplied length if the process requires a documented tail, leader or other nonusable portion. Do not subtract threading loss twice: decide whether it is already excluded from usable length or is included in S, and write that convention next to the calculation.<\/p>\n

If the full-roll usable length in a second hypothetical example is 12 meters, a 9-meter requirement budgets one full roll from zero opening stock. That does not mean one new roll must be consumed during every shift. A suitable partial roll already loaded in the printer may cover some or all of the requirement, provided its identity, condition and remaining usable length can be established under the local procedure.<\/p>\n

Separate material demand from the timing of a roll change. If the remaining loaded length cannot cover the next production block, arrange an approved change window and accessible replacement stock. The calculation does not authorize splicing, joining rolls or changing the take-up arrangement. For safe installation and release after a change, follow the cleaning roll change qualification guide<\/a>.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Input<\/th>\nUse in the estimate<\/th>\nImportant check<\/th>\n<\/tr>\n<\/thead>\n
Planned print cycles P<\/td>\nCount relevant production activity<\/td>\nUse same cycle definition as recipe<\/td>\n<\/tr>\n
Approved interval I<\/td>\nBudget periodic cleaning events<\/td>\nDo not change to reduce stock use<\/td>\n<\/tr>\n
Extra events X<\/td>\nAdd restarts and other defined events<\/td>\nAvoid double counting automatic entries<\/td>\n<\/tr>\n
Advance A in meters<\/td>\nMultiply by complete event count<\/td>\nConfirm per-event versus per-action basis<\/td>\n<\/tr>\n
Setup or discard S in meters<\/td>\nAdd documented nonproduction use<\/td>\nDo not subtract same loss twice<\/td>\n<\/tr>\n
Usable available length<\/td>\nCompare stock with requirement<\/td>\nSeparate partial rolls and held stock<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Reconcile the estimate with actual use<\/h2>\n

At the shift boundary, record the opening and closing stock basis consistently. A useful material balance is opening usable length plus issued usable length, minus closing usable length, minus unused material returned to controlled stock. Compare the resulting consumption with the planned event and loss calculation. Do not force agreement by changing the recipe entry after the event; preserve the discrepancy and investigate it.<\/p>\n

Investigate differences in a practical order. First check units and whether the same roll configuration was used. Then check event definitions, extra cleaning counts and setup losses. Finally review unplanned restarts, damaged stock and incomplete records. A discrepancy may be a documentation issue rather than a machine fault. Record what is known without assuming the roll was short or the operator wasted material.<\/p>\n

Avoid using the first observed shift as a permanent planning standard. Product mix, interruptions and setup conditions can change. Build a small history grouped by the same relevant recipe and roll configuration, then review the spread. Mark exceptional runs and explain them. This creates a better purchasing basis than a site-wide average that combines unlike printers and unrelated products.<\/p>\n

\"Two
Two unused white stencil wiper rolls separated on a clean stores shelf. Illustration based on the SWESD product reference; application suitability must be verified.<\/figcaption><\/figure>\n

Protect print quality while managing inventory<\/h2>\n

The cleaning interval belongs to the qualified process. Lower roll consumption is not a success if printing becomes less stable. Any proposal to alter intervals, feed, chemistry or sequence needs the site’s engineering change and verification process. The inventory worksheet should show the approved revision so that stores staff are not asked to judge whether a cleaning step can be skipped to finish the shift.<\/p>\n

The IPC-authored Stencil and Misprinted Board Cleaning Handbook<\/a>, available as a hosted copy of the 2007 handbook, explains the role of inspecting, monitoring and wiping the stencil underside during printing. That context matters: consumption is one part of a printing process, not a standalone optimization target. This reference does not supply your feed length or authorize the example recipe. Obtain those inputs from the actual qualified equipment and process records.<\/p>\n

Where roll handling occurs in an ESD protected area, maintain the site’s handling controls during issue and changeover. The educational video below introduces electrostatic discharge as background for that handling requirement. It does not demonstrate a printer sequence or establish roll consumption. The length model above and the controlled recipe remain the basis of the inventory estimate.<\/p>\n