Vacuum measured at the pump or generator does not prove useful vacuum at the pickup cup. A leaking hose, cracked branch fitting, contaminated check valve, blocked filter or wrong release-air path can reduce holding force or delay part release. Intermittent faults often appear only while hoses flex.
This guide maps the complete source-to-pickup path and compares static with dynamic behavior. Isolate energy and support moving mechanisms before handling hoses. Use component-specific limits rather than one generic vacuum number.
Decision matrix
| Test point | Evidence | Interpretation |
|---|---|---|
| Source | Supply pressure or pump condition and source vacuum | Establish available vacuum |
| Branch | Before/after filter, valve and check valve | Locate restriction or reverse leakage |
| Hose | Route, flex state, fittings and occlusion test | Find distributed leakage |
| Pickup | Vacuum rise/decay with blank present and absent | Separate seal from circuit loss |
| Release | Blow-off command, valve response and drop timing | Prove clean transfer |
Draw the real vacuum circuit
Identify pump or ejector, filter, reservoir if fitted, control valve, check valve, release/blow-off path, manifold, hoses and suction cups. Mark flow direction from symbols or manufacturer data. A check valve installed backward can block evacuation or trap vacuum after release.
Record which pickup fails and whether neighboring branches share the source. Compare the fault at idle, during blank contact and during other simultaneous vacuum demand. This prevents replacing a suction cup when the common source is unstable.
Inspect hoses under their moving condition
Look for hardening, flattening, abrasion, cuts at fittings and tight bend radii. Move the mechanism only through its safe manual procedure and inspect the hose at every flex position. A crack may close when parked and open only during transfer.
Check push-in insertion and thread seals without applying uncontrolled sealant. Avoid pinching a hose with pliers as a routine test. Use approved plugs and isolation points so debris cannot enter the valve or generator.
Test check-valve holding and restriction
Measure vacuum immediately upstream and downstream during evacuation and controlled decay. Confirm the check valve opens in the intended direction and limits reverse flow as designed. Slow evacuation with good holding suggests restriction; rapid decay suggests leakage, but the pickup seal and control valve must be separated.
Contamination can prevent full seating. Clean or replace only according to the component instructions. Spring force, cracking behavior, flow capacity and material compatibility matter; a visually similar check valve may change response time.
Separate cup sealing from circuit leakage
Test with the actual blank and then with an approved smooth test surface. Record time to reach the machine threshold, holding decay and pickup success. Inspect cup lip, mount, angle and blank porosity. Porous paper may require system capacity and contact-area review rather than tighter thresholds.
Use the linked pickup guide to assess cup selection and presentation. Do not increase vacuum or sensor delay until the leak path and release requirement are known.
Validate pickup and release as one sequence
Run repeated pickup, transfer and release cycles while logging vacuum switch state and PLC timing where available. Confirm release air does not leak continuously into the vacuum path and that residual vacuum does not carry a blank beyond the drop point.
Record component codes, test locations, vacuum trends and hose route. Send HANNAI photos and a sequence video with the machine model and blank material. Final acceptance requires stable handling, not merely a high source reading.
Related machine and guide
Review the HN-M100 automatic paper cup machine for machine context, then use the vacuum pickup troubleshooting guide for the adjacent check. Browse all Buyer Guides when building a wider project checklist.
Frequently asked questions
Why is source vacuum good but pickup weak?
A branch restriction, hose leak, valve fault or poor cup-to-blank seal may be downstream.
Can any check valve replace the original?
No. Direction, flow, opening behavior, materials, ports and response must match.
Why does the fault appear only during motion?
A hose crack, bend or fitting load may change as the mechanism flexes.
What should be measured dynamically?
Vacuum rise, holding decay, threshold timing and release response over repeated cycles.
Review your machine configuration with HANNAI
Send the machine model, project reference, component labels, drawings, photos and a description of the required result. We will clarify which details must be confirmed before a quotation or technical recommendation.