In the electronics industry, there are a variety of PCB Materials that vary in several aspects; all of those substances have different Lead Times. In case the material chosen is uncommon, then it may take a while to produce and deliver as it can be hard to obtain.
However, all manufacturers constantly stock the frequently chosen PCB Materials in their facility to fulfill the purchases, specifications, and purpose stated by the customer.
In this article, we will thoroughly discuss particularly the Flexible PCB Materials, and their effect on the Lead Time of the purchase. Keep on reading until the end to fully comprehend it!
What is Flex PCB Material?
As its name indicates, a Flexible PCB Material is elements that comprise bendable characteristics with a flexible film. Furthermore, the byproduct of Flexible Materials, like Flexible PCBs are popular in the consumer, automotive, medical, telecom, and aerospace industry.
Typically, the conventional PCBs are comprised of Fiberglass and Metal Base Materials. On the contrary, the material utilized in Flex Circuitry is a Flexible Polymer. Furthermore, almost every Flexible Circuit preferred a Polyimide Film for its substrate because of its qualities.
One of the fundamental advantages of employing a Polyimide Film is its performance during the heating process; it doesn’t soften when exposed to extreme temperatures at a certain level. However, even if that’s the case, it can still produce a versatile output that can still be bent and installed in intricate areas in a device, equipment, and machinery.
Along with that, the Flex Circuitry necessitates a Flex Adhesive specifically built for the layers of a Flexible PCB to bond together. It is because if the manufacturer utilizes a traditional adhesive, it doesn’t perform its job well; however, it significantly compromises the reliability, quality, and performance of the device. Hence, the experts developed the Adhesiveless Polyimide that can still link the layers and copper together without actually using an adhesive.
In-Depth Understanding of Flexible PCB Material
Different Material Selection
Generally, there are five (5) fundamental classifications in configuring the Flex PCB Material; we have its cores, copper type and weight, PSA requirements, stiffener, cover lay, and solder mask.
Thicker Flex Cores
One of the issues the manufacturers are facing that could possibly delay the delivery of the consumer’s orders is the Flex Core Thickness. Some clients preferred their boards to have a thicker core than the usual one; thus, creating a concern with the impedance requirement. Although the specified chunkier base and the employed line widths will reach the desired input impedance, the disadvantages include longer transit times because the substance is not in inventory, a thicker, less flexible architecture, and increased component costs. To achieve the impedance criteria, a reduced core, thinner threads, and thinner copper diameter can often reasonably be expected.
In line with this, the standard Flex Core Thickness per the standard guidelines varies from 0.0005 inches to 0.003 inches; however, the frequently used thickness is at approximately 0.001 inches. Nevertheless, some fabricator constantly stores thicker core options; however, they are unnecessary in some cases and it has a fewer demand. Thus, it necessitates a specialized order from the supplier. In case a thicker core is the desired preference of the customer, then we have some proposed solutions to address it, such as bonding several lighter layers together to prevent impeding production.
Copper Weight and Type
Another essential aspect to consider in constructing Flexible Circuitry is the Copper Weight and its Type. Since Flex Circuits are bendable, then it necessitates a thinner copper if possible. In that similar sense, Copper Thickness may vary from 1/3 ounce up to 1 ounce. However, the frequent thickness in such circuitry is at ½ ounce. As for the copper type, the clients may choose from Rolled Annealed, or Electrodeposited.
If the application is highly intricate and complex that demands exceptional versatility, then a Rolled Annealed would be a better option. On the other hand, we recommend Electrodeposited Copper if the application calls for straightforward bend requirements. Apart from that, if the budget is constrained, then this would be the ideal alternative.
In case the situation calls for High Current Carrying Capacity, then it will necessitate a thicker copper that could possibly slow the delivery time. However, the experienced manufacturer will produce a comprehensive solution to this concern, such as MV Flex Circuit.
PSA Requirements
To begin, the PSA stands for Pressure Sensitive Adhesive; these are requirements wherein one should decide whether it is possible to place the flex inside the convention, link it to an absorber plate for thermal dispersion, or electronically link it to another component of the fabrication. Now, the concern begins with the various PSA options since they can be pretty expensive if chosen incorrectly. On the contrary, PSAs are constantly available in stock in the manufacturer’s facility; however, the size format could be an issue.
In general, Flex Circuit Board providers engage with broader roll dimensions, and the fabrication procedures cannot be used, for instance, with a 1-inch vast sheet. In the same sense, the frequently employed PSAs range from 3M’s 467 and 9077. In case the application necessitates automated assembly, we recommend going for a 3M 9077 option.
Flex Circuit Stiffener
Simply put, there are various Stiffener Materials for Flex Circuitry, such as FR4, PI, Stainless Steel, and Aluminum. Hence, if the client decides to opt for special stiffeners for their application, then it could possibly contribute to delaying the delivery. Generally, the FR4 and Polyimide Stiffeners can be easily found in various suppliers, and are always in stock at the manufacturer’s facility.
On the contrary, Stainless Steel and Aluminum Stiffeners can be difficult to acquire since they are not in demand in the industry. Thus, they must be specially ordered to obtain. Moreover, it may be necessary to subcontract the manufacturing of the steel stiffeners, which would cause a delay in both the materials delivery and the exporting.
Coverlay and Soldermask
Similar to the Flex Cores, the Cover Lays have several thicknesses; however, some of them aren’t in demand. Thus, it may be difficult to obtain which may possibly delay the delivery time. In that same sense, the usual thickness of a Cover Lay ranges from 0.001 inches up to 0.0005 inches, particularly for purposes that have a complex situation. In terms of color, Cover Lay may vary from black, white, or traditional polyimide dye. As for its thickness, the manufacturer may limit it to 0.001 inches as a standard.
As for the Soldermask, the only concern is the color availability. As a lot of people know, the common color for solder masks is green; thus, it will be the standard stock. In some cases, manufacturers stock yellow too; however, it may be limited as its demand is not high.
Difference Between Online Lead Time and Final Lead Time
Simply put, the Online Lead Time can be referred to as the Assembly Order Lead Time wherein it only focuses on the component gatherings; hence, we always require our consumers to have a Bill of Materials ready to have the estimated Lead Time through an electronic mail.
On the contrary, the Final Lead Time is the endmost estimation of Lead. During that case, the product has already gone through audit inspections; then, it can already proceed to PCB Manufacturing, Component Procurement, and Construction. In line with this, the Total Lead Time may take a while because of certain aspects; therefore, it may take us 2-3 working days at least to process them. Occasionally, parts may become detained by authorities, that drags down the entire procedure. Normally, Bare PCBs are completed prior to receiving all of the constituent elements.
Best Practices in Selecting a PCB Material
Essentially, there are various aspects to consider in choosing the PCB Material that will contribute to shortening the Lead Time of the output.
Coefficient of Thermal Expansion (CTE)
One of the crucial factors in the substrate’s Thermal Characteristics is the Coefficient of Thermal Expansion. In essence, every constituent in a PCB has a varying CTE value that may perform differently during the production procedure. Hence, it would be beneficial to match each piece in the PCB with a similar CTE.
Substrate Weave
According to experts, selecting a robust Substrate Weave will create the dielectric constant spread evenly; hence, offering an equilibrium performance of the device.
High-Frequency Applications
In case the application will deal with High-Frequency operations, it would be better to avoid Flame Retardant properties, specifically FR4 Material since it has a significant dielectric loss that would be disadvantageous to the device.
Moisture Absorption
As its term implies, Moisture Absorption is the capability of the board to absorb and resist the presence of water fluid from penetrating the cores of the device that could potentially damage its overall performance of it. Thus, it would be beneficial to select a PCB Material that possesses this particular capability.
CAF Resistance
In case a PCB Material doesn’t have a CAF Resistance technology, it would be prone to PCB Failure related to Electrochemical Migration Process. As a result, it is advisable to select PCB Material with exceptionally good CAF Resistance. In that way, Conductive Anodic Filament (CAF) Formation and Failure would be addressed beforehand.
What is the Expected Lead Time in MV Flex Circuit?
Simply put, there are several Lead Times depending on the specification and complexity of the orders. However, in this section, we will discuss the standard lead time of the conventional boards having the usual PCB Materials installed on them.
Typically, the Overall Lead Time of a Rigid and Flexible PCB having the usual parameters is approximately twenty (20) working days, which excludes holidays. On the contrary, some employed parameters in the orders are yet to be calculated by the experts. However, MV Flex Circuit will ensure that the Lead Time of our client’s purchases will be reduced since we’re constantly enhancing our technologies and machinery. Furthermore, we are on the move to stocking more limited PCB Materials in our factory. In that way, we can deliver the consumer’s product even if it necessitates specialized orders. In MV Flex Circuit, we will provide the highest possible service we could offer to our beloved customers.
Lead Time Calculation
Summary
All of the crucial aspects related to Flexible PCB Material Affecting the Lead Time were comprehensively discussed in this article, including the factors that could delay the Lead Time, and the aspects that could help in addressing such concerns.
If you’re curious about the Lead Time of your desired order that contains Flex PCB Material, then do not hesitate to contact MV Flex Circuit to answer your question in mind. We are available day and night, seven days a week to support you with your needs; hence, send us your specifications today, and get a chance to avail our daily offers that could significantly reduce the overall cost of your purchases.
