DEFECT TOPIC
Gate stringing
Fine strands pull from the gate after mold opening and fall onto the part or into the cavity. Check resin, temperature and gate structure in order.
21 articles
Articles in this topic
View all articlesCauses of Gate Stringing: Gate Temperature, Valve Pin Timing, and Solutions
At the moment of mold opening, a thin string is pulled from the gate position, hair-like, hanging on the product or nozzle tip. If untreated, this string causes shorts on adjacent pins, damages mold surfaces, and falling debris contaminates the cavity.
Open-Nozzle Hot Runners in Connector Molding: LCP vs PA9T Field Test
Stringing and drooling in connector injection molding are often managed by machine tuning and post-processing. This field test compares open-nozzle hot runners with active temperature switching against constant-temperature runners in LCP and PA9T, focusing on gate condition and yield.
Gate Defects in High-Temperature Molding: Why Machine Settings Only Offer Partial Relief
In LCP, PA6T, PA9T and PPS molding, stringing, drooling and nozzle clogging are common gate defects. Shops usually adjust temperature, injection speed and packing time, yet the improvement rarely holds. The cause is not only the parameters: a constant-temperature hot runner has to compromise across three stages of the molding cycle.
How FHFC Hot Runner Gate Temperature Control Works
FHFC hot runners are often assumed to heat and cool the entire system continuously, raising concerns about energy use and response speed. In practice, only the gate area changes temperature; the manifold and runners remain at a constant temperature. This article explains the stage-based control logic, energy scope and structural boundaries.
Stringing, Drooling and Clogging: Differences, Causes and Countermeasures
In high-temperature molding, stringing, drooling and clogging are often grouped together as gate defects, yet their symptoms, causes and adjustment directions differ. Without identifying the defect type first, a single parameter change may relieve one issue while worsening another.
FHFC vs Standard Hot Runner: How to Assess the Cost Difference
An FHFC hot runner requires more investment than a conventional constant-temperature system, but the difference cannot be reduced to a single figure. The decision requires assessing both additional cost and measurable returns. This article outlines the cost structure, benefit sources and evaluation method; it does not replace a project quotation.
Which Molding Projects Fit FHFC Hot Runners? Four Checks
FHFC hot runners are not suitable for every molding project. The technology controls local gate temperature and targets stringing, drooling and clogging. It is not whole-mold FHFC, and does not address weld lines, surface appearance or warpage. Material, part structure, current defects and production volume provide an initial basis for assessment.
LCP Industrial Connectors: Reliability, Gate Carbon and Changeover
Industrial connectors must stay reliable through temperature swings, vibration, oils and long service. LCP suits these conditions, while high-mix, low-to-mid-volume production brings gate carbon, material changeover and maintenance challenges.
LCP Micro Connectors for Consumer Electronics: Precision Molding Requirements
Micro connectors in phones, earbuds, watches and tablets keep shrinking in pitch and wall thickness. LCP is widely used for its flow and dielectric performance, yet the smaller the part, the more gate stringing, drooling and clogging affect yield.
LCP Automotive Connectors: Gate Defects and Processing Guide
As automotive electronics grow, LCP has become more common in under-hood and high-density connectors. Its heat resistance, dimensional stability, flame retardancy and flow suit automotive electronics, while stringing, drooling and clogging at the gate remain production challenges.
Constant-Temperature vs FHFC Hot Runners: Where the Principles Diverge
The two routes differ less in controller accuracy than in whether gate temperature changes within one molding cycle. We trace the timing logic, the resulting defects and the materials each route fits.
FHFC Hot Runners vs Mold RHCM: Two Different Technology Routes
Both routes are marketed as FHFC, yet one heats the whole cavity and the other moves only the gate. We compare working scope, heating medium, cycle timing, cost structure and product fit so selection does not drift.
Why We Recommend SD Series, and When a Valve Gate Is Needed
For precision connector production, an SD Series combined with dynamic gate temperature control is usually the first recommendation. Valve Gate systems remain necessary for demanding gate appearance, surface gating, independent multi-cavity control and certain materials. This article explains the four nozzle types and the order of selection.
Buying FHFC? Four Questions That Separate the Technologies
Similar names cause costly mistakes: a supplier says FHFC, and the contract turns out to be mold RHCM with boilers, mold changes and longer cycles. The article offers four questions to ask on the spot about working scope, extra equipment, cycle impact and the defect being solved.
Why RHCM Mold Temperature Cycling Lost Favour
Mold RHCM was not a backward process; it solved real appearance problems in its time. Energy demand, cycle time, maintenance and narrow applicability have since limited it. The article revisits its peak use, walks through the four constraints and separates it from gate-level dynamic control.
FHFC Hot Runner vs Mold Fast Heat Fast Cool: What Is the Difference?
The two technologies share a name but not a working scope. Mold RHCM changes the temperature of the whole cavity and targets surface appearance. An FHFC hot runner changes only the gate and targets stringing, drooling and clogging. This article compares the working range, equipment, cost, cycle impact and selection logic.
Hot Runner Selection Guide: Constant Temperature vs FHFC
The closing part of the series turns the earlier comparison into a selection checklist: material heat resistance and shear sensitivity first, product precision and appearance second, batch size and cycle time last. It also covers the three misjudgements that most often derail a project.
Why LCP Gates Are So Prone to Defects
LCP is difficult to mold not because the machine is hard to set, but because the gate sits between high temperature and thermal degradation. High processing temperature, low melt viscosity, thermal sensitivity and the tight requirements of precision connectors combine to make stringing, drooling and clogging common. The article explains the four causes and how dynamic gate temperature control changes the timing.
How Much Can FHFC Hot Runners Save and Improve Yield?
The return from FHFC shows up in yield, downtime, labour and consumables rather than gate appearance. The article first costs out the hidden expense of constant temperature, then works through a precision-connector case, the limits of the technology and the usual misreading of purchase price.
Why Constant-Temperature Hot Runners Struggle with Stringing, Drooling and Clogging
Stringing, drooling and clogging look like machine-setting issues, but a constant-temperature gate stays molten through the whole cycle. The article explains how each defect forms, how FHFC freezes the gate before opening, and why lower temperature or shorter packing only treats symptoms.
Constant-Temperature vs FHFC Hot Runners: Principles Compared
Constant-temperature runners hold one high temperature for the whole cycle, while FHFC runners raise the gate before filling and drop it before sealing. The article compares control logic, working envelope, material fit and the order a selection decision should follow.
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