PCB Manufacturing

What to Look For in a Quick Turn Flex PCB Manufacturer

Quick turn flex PCB manufacturers

What is a Quick Turn Flex PCB?

Quick Turn PCB refers to printed circuit boards that are manufactured and assembled rapidly and electronics firms employ this process because it yields high-quality final products and is efficient in terms of both cost and time. 

The growing market for appliances and electrical gadgets means that large-scale production is required in this fiercely competitive industry and manufacturers can maintain their competitive edge in terms of both quantity and quality thanks to quick turn. Components arranged on a flexible substrate are combined with many printed circuits to create a quick turn flex PCB which can be produced in a short time. The same parts used in the design of rigid printed circuit boards are also used in these printed circuit boards and the board’s construction, which allows it to stretch into the correct form during application, is the only distinction.

What to Look For in a Quick Turn Flex PCB Manufacturer

Quick turn flex PCB surpasses the competition about demand and utilization because, as we previously said, they are widely employed in a range of electronic gadgets, and better still, they are readily twisted or bent without losing their intended usefulness. When you pick the top producer of quick turn flex PCBs, you need to take certain factors into consideration to avoid mismanagement and monetary loss.

1. Check if the Manufacturer Produces All Types of Quick Turn Flex PCBs

Since a quick turn flex PCB is used in a wide range of sectors, they have grown significantly more complicated over time and the most popular varieties of quick turn flex PCBs in use today are listed down below.

  • Single-Sided Flexible Circuits

These are the most popular and basic flex circuits available and they are printed on one side only and have a single conductor layer on a flexible dielectric sheet. These are the market’s least expensive flex PCBs and are rather simple to make because they are lightweight, and they are simple to use.

  • Double-Sided Flexible Circuits

Double-sided flex PCBs provide improved power management and circuit density by printing on both sides of a dielectric sheet connected with plated through holes and despite being more widely used due to their higher power, they cost a little more to make than single-sided flex PCBs.

  • Chips on Board (COB)

The bare chip must be glued to the soft board using conductive or non-conductive glue, and then phosphor powder of various colors must be applied to allow the chip to emit light with varying color temperatures. That is why, when installing bare chips to COB FPC, roll-to-roll installation is typically necessary as they have the specifications for FPC manufacturers’ processes. 

  • Multi-Layer Flex Circuits

Quick turn flex PCBs use three or more conductor layers and these PCBs cost more than other PCBs because of the intricacy of manufacturing and they are often employed in military and aerospace applications.

  • Rigid-flex Circuits

Rigid-flex PCBs use rigid PCBs and normal flex circuits and are widely used in commercial electronics, including laptops and smart gadgets, as well as in the military, where their strength and dependability are essential for operation.

Quick Turn Flex PCB

2. Maintenance of All the Stages in the Manufacturing Process

  • Prototype Stage

Making a PCB prototype is one of the most important steps in designing and putting together a quick turn flex PCB because prototyping these printed boards can help save expenses and time. 

The process of manufacturing prototype circuit boards involves assembling all information and sets of specifications onto the board and early in the production process, PCB prototype boards are created to enable consumers to test how the finished product will function. By letting clients alter them to suit their demands, they are utilized for inspection, and quick turn PCB prototypes frequently assist manufacturers in determining whether the original circuit board contains any flaws, which helps them increase productivity and performance. 

To put it another way, the PCB prototype stage records any feature corrections, additions and rectifications to guarantee that there are no mechanical or technical flaws in the finished product and prototype testing is therefore given adequate time to assure efficiency and simplify manufacturing. Quick turn flex PCB makers use a variety of PCBs, including functioning prototypes, and graphic models to provide clients with a clear understanding of the operation of the finished product.

  • Beta Run Stage

During this phase of production, fast turn boards are made in quantities ranging from several hundred to several thousand, and as PCB templates frequently correspond to the finished product, this phase is the most crucial one because all of the errors should be fixed at this point. All the problems that arise in the final fabrication step frequently surface in the pre-production phase, and to optimize board layout, conduct an electrical test, and verify all tooling arrangements, the beta run stage serves as a corrective ground. The variables that arise from the testing processes will show a client the beneficial changes needed to increase quality as they go from the PCB prototype stage to the production stage.  

  • Full Production Stage

PCB fabrication for consumer applications is the last step in the quick turn flex PCB standard production process and when all mistakes have been fixed and all potential manufacturing factor issues have been resolved, full production starts. Larger and significantly greater orders than those obtained in the previous manufacturing phases can be placed during this assembly step and these orders may take longer to finish. 

Customers may expect large volume printed circuit board orders at the fastest possible speed as soon as the PCB fabrication businesses finalize all design and data and the completed product may reach the proper client in the shortest amount of time, usually within 24 hours, regardless of the intricacy of the creative process. The design and engineering team will undoubtedly have an efficient manufacturing process and produce high-quality PCBs for prompt delivery if they have completed all previous PCB production phases.

Quick-Turn Flex PCB

3. Quality of the Used Materials

Quick turn flex PCBs have a polymer layer that protects the circuits and polyimide and similar polymers allow for greater heat dissipation than most rigid circuit board materials, so flexible circuits are often built using them. The quality of the flex circuit is determined by the flex PCB raw material and flex PCB stackup and three types of substrates are utilized in flexible circuit boards. Three types of substrates are adhesive polyimide, adhesiveless polyimide and polyester (PET), depending on what the customer demands.  

  • Films of Dielectric Substrate

Polyimide is a flexible material and the manufacturing technique gives polyimide its very consistent thickness, which ranges from 0.5 to 4 mils after being heat-cured, polyimide (PI) films maintain their flexibility and do not soften when heated.

  • Electrical Conductors

Thin circuit lines composed of copper are perfect for both dynamic and static applications and the copper used in quick turn flex PCB is usually 0.5 ounces in weight which is the most common weight for flex PCB copper. The maximum copper weight of 2 oz allows for the best possible combination of the thinnest construction; however, that may not always be possible depending on the type of PCB being constructed.

  • Bondply and Protective Finish

Polyimide sheets coated on both sides with B-staged acrylic adhesives make up closely, composite material and the board surface is shielded using liquid photo-imaged polymer, cover coat, photo-imaged dry film and coverlay, and these different surface treatments can prevent copper oxidation and provide a solderable surface.

  • Flexible copper-clad laminate (FCCL)

It is the core component of a quick turn flex PCB and is composed of numerous layers of foil made of copper and polyimide. FCCL provides a smaller radius for any bend or twist, and its flexibility increases as the stacked grained framework of copper transforms into an expanded diagonal construction, which makes it appropriate for applications that require flexibility.  

  • Stiffeners

When essential, all types of PCBs can be made more rigid by using PCB stiffening elements that provide mechanical assistance and these stiffeners can enhance the durability, and hardness of the board elements. Stiffener substances can be employed to reinforce solder links, increase the dissipation of heat, and enhance durability against abrasion in all sorts of PCBs.  

4. The Bendability Factor

Static boards are considered bend-to-install since they will not flex more than a hundred times in their lifetime but a dynamic board bends often and can withstand thousands of bends, and its design is more robust. The thickness of the flex circuit directly affects its flexibility because the material needs to be thinner to be more pliable. The degree of thickness of these boards varies based on several factors such as the copper layer count and adhesive thickness. The amount that the board’s area that may bend is known as the bend radius and early in the design phase, the least angle at which the flexible area may bend needs to be ascertained. You can be certain that your design will allow the necessary amount of bends without damaging the copper by doing this because the amount of layers in the circuit board determines the bend radius.  

Quick-Turn Flex PCB

5. The Stacking Method

When optimizing your flex PCB stackup, as early as feasible in the design phase, make flex board models out of mylar or stiff paper and some virtual mock-up models may be made with CAD technology. After this, you may add the basic elements and use cardboard to glue the stiff pieces to this to check if the process is correct. Think about the design and operational conditions while selecting your materials and when building a rigid-flex board, use flexible layers in the middle to stop it from sliding.

  • When trying to achieve a balanced stack-up, always try to use an even number of layers and be sure to include the required impedance and thickness for each layer.
  • Choose industry-standard programs that offer a comprehensive toolbox for planning, sketching, and modifying stack-ups in flexible/rigid-flex boards and to solve the via dependability difficulties, use the air-gap construction approach to create rigid-flex structures instead of employing flex adhesives within the stiff sections.

6. Check the Flexible Circuit Routing Process

Routing traces is a common concept to all PCB designers, but routing a flex design has some unique challenges and you have to use caution when routing close to curved terrain. To prevent damage to the holes, vias and pins must not travel through the bowed regions because such areas require traces to go perpendicular to the bend line. When piling layers with neighboring traces on top of one another, proceed with caution and always stagger the traces since this will cause the flex circuit’s bend sites to become undesirably stiff. Flex circuits have unique layer topologies, and not every layer may be accessible in every part of the board and that is why routing on layers that might suddenly drop out requires vigilance on the part of designers.  

You need to determine if stiffeners are required for the preliminary components based on their arrangement and the design of a PCB’s circuitry may make or break it. When building flex PCBs, large bend radiuses are desired since sharp angles shorten a board’s lifespan, and the stress levels are lower for curved traces than for angled ones so it is necessary to run conductors perpendicular to the overall curve. This process eliminates the stress points that may cause trace copper to shatter but on a quick turn flex PCB that has two or more layers, the traces have to be separated. Avoid creating any discontinuities like vias, cutouts, slits, or holes in the vicinity of the bend as stress and fissures that arise from bent vias eventually cause problems and failures.

During manufacturing, flex materials are more prone to shift and compress and that’s why while building your flex board, the drill to copper is crucial. Copper is exclusively applied to the via pads when button plating is used because button plating requires less copper, so it is more versatile. In complex etch patterns, manufacturers can enhance etch yields and better control copper thickness, and faster speeds are also made feasible by the constant copper thickness, and spacing of conductor traces, which also allow for controlled impedance, however, the cost of the quick turn flex PCB is increased by the extra processing steps.

7. Use of Pads

A typical element of a conductor that wraps around a through-hole is a pad, which is used for connecting wiring elements. Because of the circuit’s versatility, which might cause it to rise off the substrate’s surface, and because twisting or flexing can cause pressure that could make it harder for the copper pads to keep being attached to the bottom substance, each pad on a quick turn flex PCB has to be secured. Because of this, it’s crucial to support uncovered pads, which may be achieved by enlarging the pad area to release pressure. This is particularly important for one-sided quick turn flex PCB designs that lack a plating through-hole to aid in pad connection. 

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