How To Prevent Delamination And Prevent Secondary Circuit Failure After Overmolding Through Precise Parameter Control?
Closed-loop control for prevent delamination overmolding demands the connecting of the melt injection temperature, mold temperature, injection pressure and cooling holding time, with a connected parameter curve to completely prevent the subsequent failure, due to the parameter fluctuation.
Parameter Fixation and Locking Mechanism
Locking process parameters takes no human intervention. Once the prototype has been tested up to requirements, main parameters like injection pressure, dwell time, mold temperature are locked on the actual equipment via the PLC chip so that no operator can access them.
Mold Preheating Standard for Mass Production
Molds preheating makes the production stable. Before each start-up at least 3 molds have to be preheated to avoid fluctuations in the process due to temperature variation between the machine and the molds (needed to keep the interface bonding stable after the long-term).
Quantitative Manufacturing Case Of Complex Secondary Encapsulation Molding For JS Precision Medical Monitor PCBA
This case study highlights how JS Precision overcame the technical challenge of overmolding cracking of a medical grade multi-layer FPC rigid-flex board by the precise control of a two-color plastic multi-stage injection molding process, and fully replicating the process that resolved the failure to overmolding circuit boards.
Client Challenges:
Our customer for this collaboration was a Europe and United States medical electronics company. This company's self-design high-end medical monitor multilayer rigid-flex PCBs at after passing plastic injection overmolding at an external factory, displayed interface delamination of 0.35mm even following 5 times of thermal cycling test.
This PCB has failed a medical grade reliability testing and suspended the project. The value of the client was that of low thermal stability flexible polyimide material and low erosion resistance of micro-solder joints. So the traditional process was not suitable for the features of this ultra-slim board.
JS Precision Solution:
From the practical point of view of our precision overmolding experience for medical electronics, our group used our own cost calculation formula to develop a complete solution: Total Cost = T + (U V), in which the process optimization cost T is balanced with the long term yield benefits U times V.
1.Changed the single point jet gate to a two sided asymmetrical balanced edge submarine gate. Where the melt scouring force was reduced by 40%.
2.The temperature control mode of 4 stage for the barrel was applied per the melting characteristics of plastic.
3.120 sec vacuum plasma cleaning was included before processing to raise the surface energy of the board to 55mN/m.
4.Simultaneously, the parameters controlling mold flow were optimized, maintaining shear rate below 1100 s-1 within component to be used without causing damage.
Lessons Learned:
In the first trial mold round, a lot of flash was found at the gold finger position due to the thermal deformation in flexible section. Team rapidly improved the solution by applying micron-graded PTFE sealing gasket into system mold insert, which reduced filling time by 0.8 second and eliminated overflow issue entirely.
In the end, 100% of 1500 pieces trial production samples successfully passed 30 thermal shock tests (interface void rate < 1.5%), greatly over industry requirement.
Customer Feedback:
The client's Senior Hardware Quality Director was very impressed with JS Precision after seeing the final testing/cross-section report.
Here are some of his comments: "JS Precision have a brilliant data driven engineering approach!They totally fixed the delamination problem that had been dogging us for months. We can now see JS Precision as a strategic manufacturing partner and can have absolute trust.”
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Faced with similar complex rigid-flex PCB or multi-material precision overmolding challenges? Submit your customization requirements to JS Precision immediately to receive expert technical support and a quote.
Why Choose JS Precision As Your Long-Term Trusted Partner For Customized PCB Injection Molding And Packaging Processing?
The selection of JS Precision does not just equate a contract manufacturer, but a technology-oriented strategic partner with complete failure analysis laboratory, data support etc. The main selling point of JS is one-to-one, divisible, and highly stable customized service capability.
The brand can meet all a comprehensive range of needs from prototype prototyping to the mass production of several million units by using IATF 16949 and ISO standards.
The ISO 9001:2015 dual-system standards would give any customers a comprehensive flow of technical support by loads of DFM analyses, collaborates with CMM maps and environmental reliability tests. All the coordination is done by senior engineers has more than 10 years of experience.
It much reduces the communication gap, greatly improve the efficiency of the project and save the cost of trial-and-error.
よくある質問
Q1: What is the typical MOQ for PCB overmolding, and how exactly are costs or quotes put together?
We can do prototype overmolding for single-piece tests and then go into mass production, generally from 500 pieces. You can just upload your drawings, and we quickly estimate the price and return a quote. The total cost usually includes mold fees, plus separate processing charges per step, not only one thing.
Q2: What is the key difference between a standard plastic processing shop and a proper overmolding service provider?
Most regular plants don’t have a consistent PCBA surface treatment workflow. This gap can cause delamination, quite easily, especially when materials meet at the interface. A professional provider performs plasma pretreatment to raise the board’s surface energy to above 52 mN/m. That means the delamination risk is basically removed, no big surprise defects.
Q3: Why would people pick TPU or polyamide (PA) as the outer layer to cover an overmolding circuit board?
TPU offers strong elasticity and impact endurance, so it fits medical equipment and handheld electronics. Polyamide brings strong heat tolerance and higher mechanical strength, so it matches the protection needs of heavy-duty circuitry in industrial control, automotive electronics, and similar use cases.
Q4: How do you make sure fragile 0201 components, and those fine-pitch lead chips, do not get ruined by the high pressure during injection molding?
We use Moldflow flow-field simulation to control the melt shear rate strictly under 1200 s⁻¹. After the cavity is filled 95%, we switch to secondary holding pressure, and we slow down the finishing stage. In practice this helps safeguard the 0201 precision parts, keep them intact even under the molding cycle.
Q5: How does JS Precision really guard the IP of enterprise clients when the electronic overmolding customization becomes complicated or very “detail heavy” ?
Before any collaboration begins, a compliant NDA confidentiality agreement is signed, then an internal engineering data isolation system is put in place. In the workshop, photography is simply prohibited, and all data is sealed in a strict manner to protect the client’s intellectual property in a proper and secure way.
Q6: How can you confirm by testing that the finished product after overmolding does in fact satisfy the high bar for preventing delamination during the overmolding process ?
The finished product has to pass 100% of the 24 high-and-low temperature thermal shock tests , then it also needs ultrasonic flaw detection. This is to make sure the void rate at the overmolding interface is below 2% , so it aligns with the anti-delamination process standard and requirements.
Q7: If the solder mask peels off from the plastic after months of actual use, what are the underlying reasons, or what typically goes wrong ?
Usually it comes down to inadequate surface pretreatment and cleaning. Residual contaminants reduce the surface energy , which then weakens adhesion. Over time, long-term thermal stress accumulation can trigger delayed delamination at the encapsulation interface, even if the initial bonding looked OK.
Q8: Generally, how long is the full customization and delivery cycle from submitting 3D drawings to receiving the final encapsulated PCB?
Within 24 hours after we receive the 3D drawings, we provide a DFM review and a quotation. Prototype prototyping takes about 10-12 working days, and mass production delivery is typically 20-25 working days, consistently.
概要
Precision injection molding overmolding of PCBs is a challenging engineering task, involving many related technologies. Problems encountered during production, such as delamination, components fracture and airtightness failure, resulted from inadequate process management.
The application of strict control over surface energy parameter, solidifying low-stress mold flow curves and prototype limit test could reflect the circuit protection risk and guarantee the reliable operation equipment during prolonged period.
This kind of high-end electronical assemblies tolerates very few errors. JS Precision offers professional PCB overmolding to much reliable with our mature hands-on practice platform excellent quality-control-system. For process selection, the calculation of mass production, delaminating rectification, contact our engineer for custom DFM report and accurate quotation in time 24 hours.
免責事項
The contents of this page are for informational purposes only.JS Precision Services,there are no representations or warranties, express or implied, as to the accuracy, completeness or validity of the information. It should not be inferred that a third-party supplier or manufacturer will provide performance parameters, geometric tolerances, specific design characteristics, material quality and type or workmanship through the JS Precision Network. It's the buyer's responsibility Require parts quotation Identify specific requirements for these sections.Please contact us for more information.
Our factory is equipped with over 100 state-of-the-art 5-axis machining centers, ISO 9001:2015 certified.当社は、世界 150 か国以上のお客様に、迅速、効率的、高品質の製造ソリューションを提供しています。少量生産でも大規模なカスタマイズでも、24時間以内の最速納期でお客様のニーズにお応えします。 Choose JS Precision this means selection efficiency, quality and professionalism. To learn more, visit our website:www.cncprotolabs.com
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