Hot Plate Welding Machine FAT & SAT Checklist

Content type: Application Guide. This guide explains how to plan factory and site acceptance testing for a custom hot plate welding machine. It is not a report of a completed customer project and does not present validated production results for a specific part.

Direct answer: A hot plate welding machine FAT checklist should verify the agreed machine configuration, tooling, complete weld sequence, product-quality results, safety functions, alarms, recipe controls, cycle records, documentation and training before shipment. The SAT should repeat the critical checks after installation with approved utilities, production-intent parts and site interfaces. Neither test should rely on a generic sample count or a supplier demonstration alone. The acceptance criteria, part variants, inspection methods and required evidence must be agreed in writing before the FAT begins.

Hot plate welding machine FAT checklist review with production-intent plastic parts — Conceptual acceptance scene showing the machine, tooling, production-intent parts and recorded checks. Final FAT/SAT scope follows the signed technical agreement.

For a custom thermoplastic welding system, acceptance is more than watching a few parts complete the cycle. The buyer needs evidence that the machine, hot tool, fixtures, controls and inspection plan work together under the technical agreement. This guide avoids inventing universal leak limits, cycle times, capability targets or run quantities.

Table of Contents

What Are FAT and SAT for a Hot Plate Welding Machine?

Factory Acceptance Testing, or FAT, is the planned inspection and run-off performed at the machine builder’s facility before shipment. Its purpose is to confirm that the ordered system is built to the approved specification and can perform the agreed functions with representative parts, tooling, recipes and inspection methods.

Site Acceptance Testing, or SAT, is performed after the equipment has been transported, installed and connected at the customer’s site. It confirms that the system still performs correctly in its production environment and that site-specific utilities, guarding interfaces, material flow, data connections and operating practices do not introduce new problems.

FAT and SAT are related but not interchangeable. FAT cannot confirm destination utilities, floor conditions, peripheral equipment or networks. SAT does not justify skipping factory run-off, where machine and tooling issues are usually easier to correct.

Acceptance question	FAT at the machine builder	SAT at the customer site
Is the ordered configuration complete?	Compare the machine, tooling, controls, options and documentation with the approved technical agreement.	Confirm that shipped items arrived undamaged and are installed in their intended positions.
Can the system execute the required sequence?	Run manual, setup and automatic modes; verify heating, transfer, joining, cooling, unloading and reset behavior.	Repeat critical automatic cycles after installation and verify interaction with site equipment.
Does it make acceptable parts?	Weld production-intent parts and inspect them by the pre-approved product methods.	Repeat agreed product checks using site materials, operators, utilities and downstream processes.
Are safety and fault responses correct?	Witness the specified guards, interlocks, emergency stops, fault messages and controlled restart behavior.	Recheck safety functions affected by shipment, installation or connection to surrounding equipment.
Is the handover complete?	Review drawings, manuals, software and recipe backups, spare-parts information, calibration records and open issues.	Confirm site training, final records, issue closure and responsibility for any remaining actions.

Build the Acceptance Plan Before the Machine Is Finished

The most useful FAT documents are written during project definition, not a few days before shipment. Start with the approved quotation, technical specification, part drawings, material requirements, tooling concept, cycle description, product tests, safety responsibilities and data-interface requirements. Convert each commitment into an observable check, an acceptance source and a record.

Every checklist line should answer four questions:

What will be tested? Identify the machine function, part variant, tool, sensor, alarm, safety device, interface or document.
How will it be tested? Define the operating mode, challenge condition, sample preparation, measurement method and person responsible.
What constitutes acceptance? Reference an approved drawing, specification, risk assessment, test method or project agreement.
What evidence will be retained? Specify the record, such as a signed checklist, measurement report, cycle log, photo, software backup or issue-closure form.

Identify what FAT cannot cover, such as the customer’s MES, final downstream tester, production utilities or every molding lot. Transfer those items into the SAT checklist instead of assuming compliance.

If the project is still at the quotation stage, use Jfortune’s hot plate welding machine RFQ checklist to define the part, production and acceptance inputs before the equipment concept is frozen.

Which Parts and Materials Should Be Used During FAT?

A machine can appear stable when it is run with carefully selected “golden parts” and still struggle with normal molded variation. FAT parts should therefore represent the production conditions defined for the project. The plan should state the part revision, resin specification, molding source, cavity identity, conditioning state and acceptable incoming geometry.

Depending on the product family, representative coverage may include:

the agreed nominal production part;
all variants that use different nests, hot tools or recipes;
parts from relevant mold cavities or suppliers;
relevant dimensional conditions within the approved incoming range;
components with inserts, baffles, ports or media that affect welding;
enough material to complete setup, challenge tests, product inspection and the agreed sustained run.

The buyer and supplier should agree the quantity before FAT. There is no responsible universal number of cycles for every hot plate welding project. The required quantity depends on the product risk, cycle length, number of variants, destructive-test demand, thermal stabilization, tooling complexity and purpose of the run-off.

Incoming part checks matter because FAT should not use the welding recipe to hide a molded-part problem. Record relevant flange height, warpage, rib continuity, cavity identification and visible damage before welding. For flexible shells, Jfortune’s plastic tank fixture-design guide explains why production-intent part support and datum control belong in tooling acceptance.

Verify the Complete Hot Plate Welding Process

The FAT should demonstrate the full process, not only the joining stroke: loading, location, heating contact, hot-tool withdrawal, joining, cooling and release. Exact motions and controls depend on the project.

For each recipe and relevant variant, the team should witness and record:

correct part loading, orientation and presence detection;
fixture clamping, support and release without unacceptable marking or deformation;
hot-tool insertion and withdrawal with adequate clearance;
stable temperature-control behavior after the defined warm-up condition;
heating, transfer, joining and cooling sequence logic;
controlled position, pressure, force, displacement or mechanical-stop behavior specified for the system;
cycle completion, part release and reject routing;
recipe identification and protection against an incorrect product-tool combination.

Displayed setpoints alone are not acceptance evidence. The FAT plan should define which actual values, completion signals or independent measurements must be reviewed. If a process limit was developed through trials, compare the installed recipe with the approved process window and confirm that unauthorized changes are controlled. Jfortune’s PP hot plate welding process-window guide explains how project-specific limits can be developed before production transfer.

Confirm Product Quality with Approved Tests

Machine motion can be repeatable while the welded product remains unacceptable. FAT therefore needs both machine evidence and product evidence. The product checks should come from the customer drawing, technical specification, regulatory requirement or approved validation plan. Do not create a leak pressure, burst value, weld strength, appearance limit or dimensional tolerance during the FAT meeting.

Depending on the part, the approved checks may include:

visual inspection of the complete weld perimeter and flash condition;
final assembly height, alignment and critical functional dimensions;
leak, pressure-decay, flow, immersion or other sealing tests;
sectioning or destructive examination at defined locations;
peel, tensile, burst or functional loading when specified;
fit checks with mating components;
verification that ports, inserts, baffles, media and appearance zones remain undamaged.

Use the test fixture, instrument setup, stabilization condition and calculation method defined in the acceptance plan. Record instrument identity and calibration status. For destructive tests, agree sample selection and failure-mode records.

A production leak test is not automatically a complete weld-validation method. It may screen finished parts without revealing every incomplete-fusion condition or long-term failure mechanism. The plastic reservoir leak-testing guide explains how to select and correlate a test without transferring arbitrary limits between products.

Challenge Machine Repeatability and Thermal Stability

A brief demonstration from a cold machine provides limited evidence. Use the defined warm-up and stabilization procedure, then an agreed run that can reveal relevant drift. Observe hot-tool zones, drive stability, fixture temperature, cycle stages, part dimensions, weld collapse, inspection results and alarms as applicable.

Use normal automatic operation and production-intent loading. Record interruptions and whether the cause was equipment, tooling, part, operator, utility or inspection. Follow the specified recovery logic, including disposition of any incompletely processed part.

Do not substitute an impressive but undefined demonstration for an agreed acceptance test. Consecutive-cycle quantity, product mix and permissible interruptions must match the technical agreement. If statistical capability is required, define the characteristic, measurement system, sampling method and calculation rules before FAT.

Test Alarms, Interlocks and Abnormal Conditions

Challenge agreed faults in a controlled manner. The list depends on the risk assessment and controls, but may cover missing or misoriented parts, sensor faults, incomplete clamp motion, hot-tool position faults, temperature deviation, motion timeout, insufficient utilities and downstream equipment not ready.

For each challenge, verify:

the machine detects the condition at the correct stage;
the alarm text identifies the problem clearly enough for the intended user;
the process stops or enters the defined safe state;
an incomplete part cannot be mistaken for an accepted weld;
reset and restart require the specified operator action;
the alarm and cycle result are recorded when data logging is in scope.

Recovery is as important as detection. After interrupted heating, the logic should enforce the agreed part-disposition rule. Recipe changes, manual motions and maintenance functions should use defined access levels.

Witness Safety Functions Without Treating FAT as a Legal Shortcut

Base safety acceptance on the project risk assessment, safety concept and requirements at the installation location. FAT should confirm specified guards, interlocks, emergency stops, protective devices, safety responses, labels and reset behavior.

Standards that may be relevant include ISO 12100 for machinery risk assessment and risk reduction, ISO 13849-1 for safety-related parts of control systems, ISO 13850 for the emergency-stop function and IEC 60204-1 for electrical equipment of machines. Applicability, edition, required performance and local conformity obligations must be determined for the actual project and destination; listing a standard in an article does not establish compliance.

Review residual risks, energy-isolation information, hot surfaces, stored hydraulic or pneumatic energy, safe manual-mode behavior and maintenance access. Never bypass safety devices to complete a demonstration.

SAT repeats functions that may have been affected by transport, reassembly, utility connection or integration with other equipment. Site acceptance should also confirm that surrounding conveyors, robots, testers or guarding do not create a new hazard or defeat the intended safety sequence.

Review Controls, Recipes and Traceability

Verify operating modes, user access, recipe selection, units, alarm history, counters, languages and backups against the functional description. If tool or product identification is automated, challenge the wrong-tool or wrong-recipe condition.

Where cycle records are required, confirm stored values, part association, failed-cycle status, export and retention. A setpoint record is not the same as actual process data.

Document accepted software and recipe versions and verify readable backups. If MES, barcode or network connections cannot be completed at the supplier, identify simulated FAT evidence and finish the interface test at SAT.

What Documentation and Training Should FAT Include?

Review documentation while the machine is available for correction. The contract may require machine and tooling drawings, electrical and fluid schematics, operating and maintenance instructions, safety records, spare-parts recommendations, calibration evidence, backups and FAT records.

Training should cover operation, changeover, fault recovery, safe manual functions, cleaning, maintenance and interrupted-part disposition. Maintenance staff need the correct drawings and hazard information; operators must distinguish accepted, rejected and incomplete cycles.

Record who attended, which topics were covered and which training must be repeated at SAT. Do not assume that a supplier demonstration to one project engineer automatically qualifies production operators or maintenance technicians.

What Must Be Repeated During SAT?

SAT begins with installation verification. Confirm secure placement, removal of shipping restraints, correct reassembly, approved utility and communication connections, and absence of transport damage before energizing.

After startup, verify motion direction where applicable, sensors, heater control, utilities, safety functions and reference positions. Run dry cycles, then repeat agreed automatic-cycle, alarm, recipe and product checks.

SAT should focus especially on differences between the factory and the production site:

site electrical and compressed-air behavior under load;
ambient conditions, ventilation and hot-tool heat management;
customer-supplied conveyors, robots, leak testers or MES connections;
production resin, molded-part variation and handling time;
site operators, work instructions and changeover methods;
upstream and downstream takt, buffers and reject containment;
final guarding interfaces and maintenance access.

If SAT differs from FAT, preserve both data sets. Check transport, tool installation, utilities, part lots, measurement conditions and peripherals before changing the recipe.

Hot Plate Welding Machine FAT Checklist

Area	What to witness or inspect	Required evidence or acceptance source
Project configuration	Machine model, options, tool revisions, product variants, layout and ordered interfaces	Approved technical agreement, drawings and configuration list
Incoming parts	Part revision, material, cavity or source, representative geometry and sample status	Part records, drawings and incoming inspection results
Hot tool and fixtures	Identification, mounting, clearances, part support, clamp action, release and changeover	Tool drawings, setup sheet and approved inspection criteria
Heating system	Warm-up logic, zone control, deviation detection and defined verification method	Functional specification, calibration status and test record
Automatic cycle	Loading, heating, transfer, joining, cooling, unloading and result classification	Approved sequence description and recorded cycle observations
Product quality	Visual, dimensional, leak, strength or functional tests required for the actual part	Customer drawing, product specification and approved test method
Repeatability	Agreed sustained run, variants, interruptions, cycle-stage trends and inspection results	Pre-approved run-off plan and signed data report
Fault handling	Sensor, temperature, motion, utility, part-presence and downstream-ready challenges	Alarm list, functional specification and fault-challenge record
Safety	Guards, interlocks, emergency stops, reset, safe state and residual-risk information	Project risk assessment, safety validation plan and applicable requirements
Recipes and access	Product selection, limits, permissions, change history, backup and restore	Control specification and accepted software/recipe version list
Traceability	Part association, actual process data, rejected-cycle status, export and retention	Data-interface specification and sample records
Documentation	Manuals, schematics, drawings, parts list, maintenance plan, backups and certificates	Contractual document register with revision status
Training	Operation, changeover, alarm recovery, maintenance and safety topics	Training agenda, attendance and open training actions
Issue closure	Deviation description, owner, target date, retest requirement and shipment condition	Signed punch list and documented disposition

Common FAT and SAT Mistakes

Testing without a frozen acceptance plan. This turns the event into a negotiation about what “good” means. Approve the methods and criteria in advance.

Using only selected parts. A perfect demonstration with unrepresentative samples says little about production variation. Identify lots, cavities, variants and incoming conditions.

Changing multiple settings during the run-off. Uncontrolled tuning destroys the evidence trail. Record the original condition, reason for change, revised recipe and parts affected.

Ignoring interrupted cycles. Stops reveal recovery and containment weaknesses. Record the cause and verify part disposition.

Shipping with vague open items. Every deviation needs an owner, due date, acceptance impact and retest decision. Distinguish cosmetic completion work from an issue that invalidates the result.

Repeating FAT without addressing site differences. SAT must examine utilities, integration, operators and production material, not merely reproduce the factory checklist mechanically.

Information to Send Jfortune Before FAT Planning

Provide approved part data, resin specifications, variants, cavity plan, production-intent samples, quality methods, production conditions, traceability needs, site interfaces, safety responsibilities and document requirements. Identify customer-supplied equipment and functions reserved for SAT.

Jfortune can then align the machine, hot tool, cold fixtures, controls and acceptance records with one project-specific plan. For non-standard parts or automation, review the custom hot plate welding machine process and the hydraulic hot plate welding platform.

Frequently Asked Questions

Who should attend a hot plate welding machine FAT?

The supplier should provide the project and technical representatives required by the scope. The buyer normally involves engineering, manufacturing, quality, maintenance and safety personnel. Ensure people authorized to judge product tests, safety functions and deviations attend.

How many parts should be welded during FAT?

There is no universal quantity. Cover setup, relevant variants, destructive tests, stabilization, fault recovery and the agreed sustained run. Product risk, cycle time, tooling and expected variation should determine the pre-approved quantity.

Can FAT establish the production weld recipe?

FAT may confirm an already developed recipe under controlled rules, but it should not replace process development. The joint, material, fixtures, measurements and tests should be mature enough that run-off evaluates the machine.

Should leak testing be included in FAT?

Include it when leak performance is approved and the required tester, fixtures and parts are available. Method, pressure, stabilization, time and limit must come from the product plan. Document any temporary factory method and repeat the final method at SAT.

Is a successful FAT enough to release the machine for production?

No. FAT supports shipment acceptance under factory conditions. Installation, utilities, integration, training and production material still require SAT and any separate customer qualification. The stages may share evidence, but they support different decisions.

What happens if an alarm occurs during the sustained run?

Record the alarm, time, machine state, part status, cause and action. Apply the agreed interruption rule. The acceptance plan determines whether the run continues, restarts or needs focused retesting.

Can FAT and SAT use different test equipment?

They can, but correlation must be understood. Record each instrument, fixture, method and condition. If FAT uses temporary equipment, define what its result proves and what must be repeated with the final SAT system.

What should be on the final FAT punch list?

List every deviation with its contractual reference, safety or performance effect, owner, due date, closure evidence and shipment status. Both parties should retain the approved revision and any SAT conditions.

Plan Acceptance Around the Actual Product

A useful hot plate welding machine FAT checklist converts project requirements into observable tests and retained evidence. It verifies more than machine motion: production-intent parts, tooling, weld quality, safety behavior, alarms, recipes, documentation and recovery from abnormal conditions all matter. SAT then confirms that this accepted system remains correct after installation and integration.

Contact Jfortune and send your part drawings, material specifications, variants, product tests, site interfaces and acceptance requirements. We can review the welding cell and help define a FAT/SAT scope based on the actual application rather than a generic demonstration.

What Should a Hot Plate Welding Machine FAT and SAT Include?