A monthly output headline is not a delivery plan. The useful question is whether the proposed order can pass through the actual factory, suppliers, approvals and logistics route by the required dates.
Capacity is a time-phased ability to complete a defined product mix, not a single number printed in a presentation. Two orders with the same frame count can consume very different engineering, machining, finishing, glazing, testing, inspection and packing resources. A defensible review therefore starts with the buyer's released scope and required milestones, maps each configuration through its actual route, overlays existing commitments and tests the remaining headroom at the bottleneck. The conclusion should state the conditions under which the date is feasible, the evidence still missing and the trigger for replanning—not repeat an unsupported annual or monthly claim.
Decision boundary: This is a buyer-side evidence framework, not a capacity certification or schedule guarantee. It does not verify any Cavorlen facility, output, staffing, equipment, order book, supplier, lead time or delivery date. Only authorised, current and project-specific records can support a commitment.
1. Turn the promised date into a controlled commitment basis
Before asking whether a factory has capacity, define what must be delivered. Record legal buyer and supplier entities, project and package identifiers, unit marks, quantities, configurations, approved alternates, required evidence, packing method, delivery point and the dates for design closure, samples, first-off approval, production releases, inspections and shipment. Distinguish a requested date from a supplier-committed date and both from the current forecast.
Define the clock-start event. A quotation that says '45 days' is ambiguous if it does not say whether the period starts at deposit, approved shop drawings, glass confirmation, colour sample approval, receipt of free-issue components or release of a complete production batch. List buyer-controlled, supplier-controlled and third-party prerequisites. A schedule should not show production starting while the governing configuration is unresolved.
Use stable configuration and schedule revisions. ISO 10007 describes configuration identification, change control, status accounting and audit; ISO 21502 provides project-management guidance including planning and control. Neither source supplies a factory's answer. Their useful discipline is to connect every capacity analysis to the exact scope and assumptions in force when it was prepared.
| Control field | Required record | Owner | Status/date effect |
|---|---|---|---|
| Scope baseline | Marks, quantities, configurations and revision | Buyer + supplier | Unreleased items excluded or separately forecast |
| Clock-start event | Contract-defined complete-input event | Contract owner | Record actual closure date; do not backdate |
| Evidence gates | Samples, tests, calculations, certificates and approvals | Named authorities | Affected work held until disposition |
| Delivery milestone | Incoterm/location, shipment lot and required date | Commercial/logistics owners | Separate factory-ready from delivered-on-site |
| Working calendar | Shifts, holidays, planned shutdowns and permitted overtime | Factory schedule owner | Current authorised calendar only |
| Change rule | Who may change scope, priority or date | Authorised parties | Rebaseline and preserve previous forecast |
2. Build the product-family routing before calculating capacity
Group units by the work they consume, not only by appearance. A fixed window, large lift-slide door, shaped unit and tested mock-up can share aluminium but follow different engineering, cutting, machining, cornering, reinforcement, coating, glass, hardware, assembly, inspection, handling and packing routes. Identify outsourced processes and return inspections. Mark re-entrant work such as rectification or re-coating rather than assuming every unit passes once.
For each family, record the unit of capacity that matches the resource: machine minutes, coating rack area, glass square metres, assembly labour-hours, test-rig slots, packing-rack positions or qualified-person availability. Frame count can remain a commercial summary, but it cannot safely replace the resource drivers. State setup and changeover logic, minimum batches and sequence dependencies where current records support them.
Link each operation to an objective record: controlled router, recent comparable traveller, machine programme, production log, subcontract order, inspection plan or observed work. A process map prepared solely for a sales visit is a hypothesis until reconciled with current records and physical flow.
| Operation | Configuration driver | Capacity unit | Primary evidence | Hold/transfer risk |
|---|---|---|---|---|
| Technical release | Unique details and unresolved interfaces | competent-person hours / release lots | Drawing register and release history | Approval or evidence gap |
| Profile preparation | Sections, lengths, machining and reinforcement | machine minutes / batches | Router, programme and recent production log | Tooling, setup or profile shortage |
| Finish | Colour, treatment, rack geometry and external provider | rack area / batches / supplier slots | Purchase order, provider confirmation and incoming checks | Rework, colour match or transport |
| Glass | Make-up, size, heat treatment and processing | m² / supplier batches | Approved make-up and supplier commitment | Breakage, remake or evidence hold |
| Assembly/glazing | Opening type, hardware and unit mass | labour-hours / stations | Work instruction and actual output history | Qualified labour and component completeness |
| Inspection/testing | Lot, witness and project method | inspector hours / rig slots | ITP, booking and record history | Failed result or unavailable witness |
| Packing/loading | Rack design, sequence, dimensions and mass | rack/container positions | Packing plan and logistics booking | Late accessory or unsafe load plan |
3. Reconcile available capacity with current and protected load
Ask for a time-phased load view at the constrained resources, not an unrestricted customer list. It should show firm work, already released work, protected service or remake capacity, planned maintenance, approved shutdowns and the proposed order by week or another suitable period. Confidential customer identities can be replaced by stable codes while retaining quantities, routings, dates and status needed for review.
Use demonstrated effective capacity rather than catalogue speed. Reconcile nominal hours to authorised shifts, staffing, maintenance, changeover, normal inspection, recent yield and other losses recorded by the factory. Do not force one generic utilisation percentage into every operation. Investigate large differences between schedule assumptions and recent comparable actuals.
The U.S. Government Accountability Office Schedule Assessment Guide explains that a reliable schedule should be comprehensive, well constructed, credible and controlled, and that resource constraints affect schedule realism. It is written for government programmes, not window factories, but its schedule-quality tests are valuable: activities should be logically linked, critical or near-critical paths visible, resources considered, uncertainty analysed and progress updated from actual status.
| Period/resource | Demonstrated available capacity | Firm existing load | Protected loss/reserve | Proposed order | Headroom/action |
|---|---|---|---|---|---|
| Week [x] / technical release | [record basis] | [coded load] | Leave/urgent corrections | [hours/lots] | [calculate and disposition] |
| Week [x] / machining cell | [recent actual basis] | [coded load] | Maintenance/changeover | [minutes/batches] | [record] |
| Week [x] / external finish | [supplier-confirmed slots] | [committed batches] | Reject/remake allowance basis | [rack area/batches] | [record] |
| Week [x] / assembly family | [qualified shifts/stations] | [coded load] | Training/absence basis | [labour-hours] | [record] |
| Week [x] / test or witness | [booked slots] | [existing bookings] | Retest contingency | [slots] | [record] |
| Week [x] / packing space | [safe positions] | [occupied positions] | Dispatch uncertainty | [racks] | [record] |
4. Test material and external-provider dates as part of the same schedule
A factory can have empty machines and still miss the date. Create a configuration-linked bill-of-material risk list covering profiles, finish, glass, spacers or sealants, hardware, fasteners, screens, motors, labels and packing materials. Record approved source, specification or drawing revision, quantity, stock status, purchase-order status, supplier acknowledgement, promised date, required-at-factory date and applicable incoming evidence.
Treat a quotation lead time as planning input, not a commitment. Obtain current written confirmation for long-lead or single-source items and reconcile it to the exact configuration. Check whether a substitution would require technical, appearance, certification, sample or buyer approval. A promised substitute is not schedule recovery until its suitability and authority are closed.
ISO's Auditing Practices Group guidance on external providers discusses risk-based control of externally provided processes, products and services. The paper is educational guidance, not certification evidence. The practical lesson is that outsourced finishing, glass and hardware remain inside the delivery system: selection, requirements, monitoring, verification and change control need visible owners.
| Item/configuration | Required date | Current evidence | Gap or dependency | Recovery authority |
|---|---|---|---|---|
| Project-specific profile/finish | [date] | Stock allocation + provider acknowledgement | Colour sample/re-coat risk | Named technical and buyer authority |
| Glass make-up | [date] | Approved build-up + supplier commitment | Heat treatment, coating, processing or remake | Glass/project authority |
| Hardware set | [date] | Exact part/BOM + confirmed quantity/date | Mass, finish, handing or compatibility | System/hardware/project authority |
| Sealants/consumables | [date] | Approved product, shelf life and stock | Compatibility, storage or destination requirement | Specified competent authority |
| Packing/racks | [date] | Approved packing concept + material booking | Dimensions, lifting, ISPM 15 or sequence | Packing/logistics/safety owners |
| Proposed alternate | before affected release | Difference and supporting evidence | Approval/test/certification effect | No use before authorised disposition |
5. Stress-test the date and control the recovery plan
Run scenarios at the real constraint: late approval, glass remake, external finish rejection, critical equipment outage, inspector unavailability, packing-rack delay or a changed release sequence. Avoid adding an unexplained blanket buffer. State which event the allowance addresses, where it sits, whether it is consumed and who can authorise its use.
A recovery action must be technically and operationally credible. Overtime requires authorised staffing, fatigue and safety controls. A second line requires equivalent tooling, instructions, competent people and verification. An alternate provider requires qualification and configuration review. Shipping partial lots can help only if the site, packing, documentation and installation sequence can accept them. Never improve a forecast by deleting inspections or hiding rework.
Set update triggers: configuration release, material acknowledgement, first-off completion, weekly actual output, forecast variance, critical-path movement and approved change. Report original commitment, current forecast and variance reason separately. A repeatedly moved baseline erases the evidence needed to manage recovery.
| Scenario | Schedule effect | Early indicator | Permitted response | Required evidence |
|---|---|---|---|---|
| Drawing approval late | Affected release shifts | Open critical RFIs | Re-sequence unaffected approved families | Mark-level release and dependency record |
| Long-lead material slips | Operation starved | Supplier acknowledgement variance | Authorised alternate or lot resequence | Applicability approval and new commitment |
| Yield/remake event | Capacity and material re-consumed | NCR/rework trend | Contain, disposition and reforecast | Affected quantity, root cause and verified correction |
| Constraint outage | Queue moves to next available period | Maintenance/condition signal | Approved repair or qualified equivalent route | Capability and inspection equivalence |
| Expedite request | Other commitments or risk may move | Negative float/priority change | Authorised priority and resource plan | Impact on all protected commitments |
| Partial shipment | Earlier subset, added interfaces | Completed releasable lot | Use only if contract/site/logistics accept | Release, packing and receipt plan |
Defensible conclusion: The date is conditionally feasible for the stated configuration and release sequence, based on the cited current records. List unresolved inputs, constrained resources, protected assumptions, update date and the event that requires replanning.
FAQ
Is monthly window output enough to verify capacity?
No. It may describe historical volume but not the product mix, resource demand, current load, material status or time-phased headroom for this order.
Should a buyer request the factory's complete customer list?
Usually not. Stable coded orders can preserve confidentiality while showing route, load, status and dates needed for a capacity review.
Can stock aluminium prove the schedule?
No. The exact section, alloy/temper, finish, quantity, allocation and condition must match the approved configuration, and all other constraints still apply.
Does adding a night shift immediately double capacity?
No. Qualified staffing, supervision, maintenance, material flow, inspection, yield, safety and downstream constraints determine effective output.
What is the most useful capacity evidence?
A reconciled project routing and time-phased constrained-resource plan supported by current load, material commitments, recent comparable actuals and named assumptions.
Can a capacity audit guarantee on-time delivery?
No. It improves the basis for a decision. Contract controls, ongoing actual-versus-plan updates, change control and timely corrective action remain necessary.
Should an urgent date remove inspection gates?
No. Recovery should not be created by concealing defects, bypassing authorised approvals or deleting required safety and quality controls.
How often should the forecast be updated?
At the contractually defined cadence and whenever a material trigger changes the critical path, scope, release, external commitment or demonstrated output.
Continue the project review
Connect this guide with the proposed window and door systems, then review how Cavorlen approaches manufacturing and quality control. When your schedule is ready, send it through the project review form.
Official sources used
U.S. GAO — Schedule Assessment Guide: Best Practices for Project Schedules ↗ISO 21502:2020 — Guidance on project management ↗ISO 10007:2017 — Guidelines for configuration management ↗ISO 10005:2018 — Guidelines for quality plans ↗ISO 9001 Auditing Practices Group — External providers ↗ISO 9001 Auditing Practices Group — Evidence collection ↗ISO 9001 Auditing Practices Group — Library and disclaimer ↗Related buyer guides
This guide does not publish or imply Cavorlen production capacity, utilisation, backlog, material availability, labour productivity, yield, equipment performance, shipment frequency or project lead time. It does not approve overtime, safety compromises or an accelerated programme. Dates, quantities, cycle times, yields and resource availability must remain placeholders until supported by authorised current records and a responsible schedule owner.