A: If we have stock, MOQ 3000pcs. | B: If out of stock, MOQ is 10000pcs.
Views: 0 Author: Site Editor Publish Time: 2026-11-10 Origin: Site
A piston that stops short leaves product in the jar, and the cause is usually fixed before the mold is cut. Airless jar packaging moves a follower plate up the body as the pump draws down, so every complaint about a short dose, a slow prime or a residue left in the base traces back to a geometry decision made in the tooling phase.
Diagnosis follows the same order as the development process. A travel fault is a clearance question, a priming fault is a valve and vent question, and a residual fault is a base and piston geometry question. Treating all three as one defect sends a buyer back to the drawing board when only one dimension is wrong.
The brief should state the dose in grams, the number of doses per fill, the acceptable residue at end of life and the viscosity range the formula will occupy. Those four items set the piston stroke, the pump chamber volume and the clearance between the follower and the wall. A brief without them produces a drawing the supplier must guess at.
Viscosity range is the item most often missing, and it is the one that causes the most rework. A formula that thickens on standing needs a piston with more drag to follow the product down, while a thin emulsion needs less drag to avoid stalling the pump. One drawing cannot serve both without a stated range.
Fix the interface before the aesthetics. The neck finish, the collar thread and the actuator travel belong in the brief, because the actuator stroke sets how far the piston is expected to move per pump. A brief that opens with shape and color delays the decisions that determine whether the pack works.
The model review should test interference at full travel, not at the rest position. A follower drawn at mid-body can look correct while fouling the base radius at the end of the stroke, which produces the short dose the buyer will later report as a pump fault. Ask for a section at both extremes.
Draft angle on the inner wall decides whether the piston follows smoothly or sticks. Too little draft and the piston binds at the shoulder, too much and the seal loses contact as the follower descends. The model should show the wall as a draft, not as a nominal diameter, and the drawing should state where the diameter is measured.
The floor plan, meaning the two-dimensional drawing issued with the model, is what the toolmaker actually works from. A model without a dimensioned plan leaves the bore diameter to interpretation, and an interpreted bore is the source of the clearance variation that appears later as inconsistent priming across cavities.
The site describes mold making through computer numerical control machining and three-dimensional printing, with mold materials selected from glass, plastic, bamboo and wood. The route chosen for a plastic airless jar decides the surface finish inside the bore, and bore finish is what the follower slides against.
A polished bore reduces friction variation between cavities, which shows up as a tighter spread in dose weight. The cost consequence is real: polishing adds operations, and a buyer who specifies a dose tolerance without paying for bore consistency has specified a result the tool cannot deliver. State the requirement, then accept the route that meets it.
Cavity count is the second cost decision. More cavities lower the piece price and widen the natural variation between units, because each cavity has its own bore and its own piston fit. A buyer running a small batch should ask whether a lower cavity count would produce a more consistent pack at a price that still works.
Appearance inspection catches the defects a functional test cannot see. A sink mark at the base of an airless jar changes the internal volume, and a short shot at the base corner creates a step the follower cannot pass. Both read as cosmetic faults and both behave as functional ones.
Set the inspection points before the samples arrive. Look at the base interior, the shoulder transition, the thread start, the collar seat and the gate witness. A gate witness on a sealing surface is a leak path, while the same witness on a hidden base is only an appearance note.
Judge samples against the drawing, not against the first sample. A buyer who approves by comparison to the previous round accepts drift, and drift in an airless pack accumulates in the clearance. Keep the first approved sample sealed and labeled, and measure each new round against the drawing.
Four tests belong before the production run: dose weight across the fill, priming strokes to first product, travel to the piston stop, and residual product at end of life. Each needs a pass criterion written in advance, or the test becomes a demonstration rather than an acceptance gate.
Priming deserves its own protocol. Count the strokes from first actuation to a full dose, repeat it after a rest period, and repeat it at the lowest expected storage temperature. A pack that primes in two strokes when warm and eight when cold will generate complaints in a winter shipment.
Residual is measured by weight, not by eye. Weigh the unit before use, dispense to the stop, then open and weigh the remainder. The figure should be compared with the brief rather than with a competitor's pack, because the acceptable residue depends on the formula's value and the pack's positioning.
Approval should freeze a revision, not a shape. Once a sample is signed, the drawing, the model and the specification carry a revision letter, and any change to the piston material, the bore finish or the collar thread raises that letter. A silent change to a piston compound alters drag without altering appearance.
Buyers should ask what triggers a new revision and who signs it. A supplier who treats a material substitution as an internal matter can deliver a pack that looks identical and primes differently, and the buyer discovers it in a customer complaint rather than in a document.
The approved sample should be stored with its revision letter attached. When a dispute arises, the sealed sample is the reference and the letter proves which drawing it represents. Without both, the conversation returns to opinion, and opinion favors whoever holds the tooling.
Ownership of the mold should be stated in writing before the first sample, not after a disagreement. The question has three parts: who owns the tool, who holds it, and who may move it. A buyer who assumes ownership without a document owns an argument rather than a mold.
Documentation should travel with the tool. That means the drawing set at the current revision, the model file, the cavity layout, the maintenance record and the list of spare inserts. A tool without its documentation is difficult to repair and almost impossible to transfer to a second molder.
Change documentation protects the buyer after the launch. Every modification should be recorded with a date, a reason and a revision, including polishing passes and insert replacements. A pack that changes behavior after two years of production is usually a tool that was maintained without a record.
Airless faults are cheap to prevent and expensive to diagnose. A brief that states viscosity and residue, a model checked at full travel, a bore finish that matches the dose requirement and a revision letter that survives approval together remove most of the reasons a piston stops short or a pump refuses to prime.
Guangzhou Ruijia Packaging Products Co., Ltd. has concentrated on packaging products for more than 15 years and integrates production with research and development, which keeps tooling, sampling and functional testing inside one development sequence. A buyer who writes the acceptance criteria before the first sample gets a pack that can be measured, not merely admired.
Air must leave the pump chamber before product can fill it. The number of strokes depends on the chamber volume, the viscosity of the formula and how much air entered during filling. A pack that needs many strokes usually has a chamber larger than the dose requires or a fill that trapped air near the valve.
By weight. Weigh the full unit, dispense until the pump stops delivering, then open the jar and weigh the remaining product. Comparing that figure with the brief shows whether the piston reached its stop or stalled short, and the two causes need different corrections.
Often yes, if the piston is a separate component and the body bore is unchanged. A different piston compound can change drag without touching the tool. Confirm that the replacement is dimensionally compatible with the existing bore and re-run the priming and dose tests before accepting the change.
Uneven wall draft, an off-center base radius or a follower that is too short for its diameter. A tilted piston breaks contact on one side and lets product pass, which shows up as a smear on the wall and a residue at the base. A section drawing at full travel usually reveals the cause.
The buyer should hold a complete copy, whatever the ownership arrangement. Drawings, model files, cavity layout and maintenance records are what allow a tool to be repaired or moved. A supplier who will not release a drawing set is describing a relationship rather than a service.