Technical Library | 2015-08-25 13:51:27.0
The stencil printing process is one of the most critical processes in the electronic production. Due to the requirement: "faster and smaller" it is necessary to place components with different paste volume close together without regard to solder paste printing. In our days it is no longer possible to control the solder paste volume only by adjustment of the aperture dimensions. The requirements of solder paste volumes for specific components are realized by different thicknesses of metal sheets in one stencil with so called step stencils. The step-down stencil is required when it is desirable to print fine-pitch devices using a thinner stencil foil, but print other devices using a thicker stencil foil. The paper presents the innovative technology of step-up and step-down stencils in a laser cutting and laser welding process. The step-up/step-down stencil is a special development for the adjustment of solder paste quantity, fulfilling the needs of placement and soldering. This includes the laser cutting and laser welding process as well as the resulting stencil characteristics and the potential of the printing process.
Technical Library | 2022-10-11 17:27:08.0
Lead-free flux technology for electronic industry is mainly driven by high soldering temperature, high alloy surface tension, miniaturization, air soldering due to low cost consideration, and environmental concern. Accordingly, the flux features desired included high thermal stability, high resistance against burn-off, high oxidation resistance, high oxygen barrier capability, low surface tension, high fluxing capacity, slow wetting, low moisture pickup, high hot viscosity, and halogen-free. For each of the features listed above, corresponding desired chemical structures can be deduced, and the impact of those structures on flux residue cleanability can be speculated. Overall, lead-free flux technology results in a greater difficulty in cleaning. Cleaner with a better matching solvency for the residue as well as a higher cleaning temperature or agitation are needed. Alkaline and polar cleaner are often needed to deal with the larger quantity of fluxing products. Reactive cleaner is also desired to address the side reaction products such as crosslinked residue.
Technical Library | 2019-10-18 10:37:25.0
It usually does not make any logic to invest in costly fabrication equipment in case you just desire to spin some prototypes and rather outsource your Printed Circuit Board assembly as well as prototype fabrication to a trustworthy vendor. I would provide a few tips as to what to consider when seeking a contract manufacturer. The two most common procedures associated with Printed Circuit Board Assembly are through-hole technology and surface mount technology. Talking about the difference between through-hole technology and surface mount technology. Through-hole elements have metal leads, & these metal leads are supplied through-plated holes inside the circuit board. On the other hand, SMT elements might or might not have leads, nevertheless most significantly, they are developed to be soldered onto the surface of the circuit boards straight on the same side as the element body. A lot of contract manufacturers would provide a quick quote mechanism over their site for the fabrication of circuit boards as well as assembly of prototypes. This would bank your time when comparing various vendors. Ensure that the quote system facilitates you to fill your details, for instance, board material, thickness, copper thickness, milling, etc. in order that you can avail of a precise quote devoid of any surprises afterward. And this is quite necessary. Typically the cost per board would decline as quality upgrades. This is owing to the fairly high setup price of circuit board fabrication over and above component assembly. A few vendors would employ a system where they unite boards from various consumers. This manner the setup price would be circulated among numerous clients. When you fabricate an item, you clearly don’t desire to have to fabricate a big quantity of boards straight away whilst you improve your design. One restriction with small quantity prototypes though is that the option of materials & material thicknesses would be constrained. In case you are employing a particular material then opportunities are there will not be any other clients employing the same material. Additionally, lead time plays a major role in indecisive prices. A longer lead time facilitates the fabricator more liberty in slotting your fabrication. This is basically reflected in cheaper prices that would view in the quote section. Clearly, if you are in a hurry and desire to be moved to the summit of the pile you would require splurging more dollars. Ensure that your contract fabricator would support the file sort for producing which you offer. The most general format for printed circuit board fabrication is the Gerber format nonetheless a few vendors would moreover embrace board files from general printed circuit board software products. A few suppliers also provide in house printed circuit design. Even in case, you create your board yourself, choosing a vendor with design services might prove resourceful in case there is an issue with your files. In this scenario, your vendor could make swift changes that would neglect pricey delays. If you are looking for an Electronic Manufacturing Services (EMS Assembly) provider, then the web is the best to search.
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