What is a 4 Layer Flex PCB?

You will have a lot of usage options with this type of multilayer Flexible PCB.

The usual Flex PCB applications are in line with the typical applications.

You’ll probably use this for mobile use, the semiconductor industry, or the medical industry.

This kind of circuit board’s flexibility makes it ideal for use in applications requiring a lot of repetitive bending.

Get Our Best Quotation

Unbeatable 4 Layer Flex PCB Quality

Outstanding thermal conductivity and excellent insulation are both features of all our Flex PCBs.

Since PCBTok only uses premium materials, you can be sure that our products will last a long time.

Because our customers are so important to us, we always take into account their needs and demands.

Please get in touch with us right away if you require a custom flex PCB of any layer, not just 4-layered!

The company wouldn’t have lasted 12 years in the market if PCBTok’s products and services weren’t of the highest caliber.

Read More

4 Layer Flex PCB By Feature

Polyimide 4 Layer Flex PCB

With polyimide as the main material, surface finishes for this type of Flex PCB includes ENIG, ENEPIG and Immersion Silver.

Wireless 4 Layer Flex PCB

The PTH is used for Flex PCB of many layers like this one. Some of these boards also feature microvias.

Mobile 4 Layer Flex PCB

Mobile PCBs that are flexible are used in mobile devices, with smartphones and tablets serving as the best examples.

Dupont 4 Layer Flex PCB

The DuPont corporation, which manufactures the Pyralux line for Flex PCB, is regarded as the top supplier of flex material.

Taiflex 4 Layer Flex PCB

You can order a variety of raw flex PCB materials that are used on multilayer boards too using the Taiflex brand.

Customized 4 Layer Flex PCB

Through SMD technique, using Flex PCBs with ICs is possible. This makes the board design complex.

4 Layer Flex PCB by Copper Thickness (5)

What Materials are Used in the 4 Layer Flex PCB?

The best thing about this type of PCB is that no other design solution can fit where this product is shaped to fit.

There are components that must come together for this effectiveness to be achieved.

These are the components used to create this type of board.

  • Mainly, polyimide
  • Adhesive, like copper-clad flex laminate
  • Coverlay, especially, when attaching this layer to a rigid board.

Most of the raw materials are usually sourced via a PCB manufacturer, or you can order them yourself from the PCB material supplier.

What Materials are Used in the 4 Layer Flex PCB
Explain the 4 Layer Flex PCB Stack-up

Explain the 4 Layer Flex PCB Stack-up

As a rule, the total thickness of the thinnest type of the 4 layer PCB is 0.282 (+/–.03mm). But there are other thicker options, as the thickest can reach 0.45mm.

Copper thickness matters because you need to factor in PCB trace and current carrying capacity.

The following make-up the PCB stack-up for this multilayer flex board:

  • Coverlay (which is polyimide + adhesive)
  • Copper trace + adhesive
  • Another layer of Copper trace + adhesive
  • Bottom layer of coverlay again

What are Applications for the 4 Layer Flex PCB?

The 4 Layer Flex PCB has a wide range of uses.

Many customers of this type of PCB have applied it to the following industrial sectors:

  • Medical tools – those that need to be bent to fit MRI machines, probing tools, etc.
  • Automotive use – these can be deployed for the engine, the entertainment system, etc.
  • GPS and navigation tools – these can be wearable PCB types too
  • Mobile devices, like the ubiquitous smartphone
  • Commercial usage, like those in machinery and power modules
What are Applications for the 4 Layer Flex PCB

Where Do I Find a 4 Layer Flex PCB Manufacturer?

Where Do I Find a 4 Layer Flex PCB Manufacturer
Where Do I Find a 4 Layer Flex PCB Manufacturer 2

Flex PCBs like this one can be easily bent into any shape needed by the device’s design because they are so adaptable.

This is especially true for the 0.5 oz ones, which are the thinnest. They are simple to manufacture and assemble into finished products.

Especially when done by a skilled PCB fabricator—PCBTok is one such manufacturer.

They are additionally well suited to harsh environments thanks to your dedicated PCB maker.

Call us right away for your 4 Layer Flex PCB orders.

4 Layer Flex PCB Fabrication

What are the Benefits of Using 4 Layer Flex PCB

Flex PCBs, particularly multilayer ones like this, are required for the task that are necessary in the digitalized world.

You will reap the following benefits if you use this type of board compared to Rigid PCBs:

  • End-product miniaturization can be achieved
  • It lasts in high temperature scenarios
  • If the end product is used 24/7 non-stop, that is survivable too
  • Microcontrollers, DiP (both ceramic and plastic types)
4 Layer Flex PCB User Tips

When using this number of Flex PCB layers, you must take the following factors into consideration.

First, there are issues with bending. Is your product a flex PCB that can be folded once and then installed? A dynamic Flex PCB product, perhaps?

Next, what is your PCB routing for this product, exactly? It must completely address electrical connections among all flex layers.

Finally, you might have to decide which PCB schematic software is best.

4 layer flex pcb banner 2
The Superior 4 Layer Flex PCB by PCBTok

We answer all inquiries at once,

Ask PCBTok about flex PCB of any layer right away!

4 Layer Flex Production Details As Following Up

NO Item Technical Specification
Standard Advanced
1 Layer Count 1-20 layers 22-40 layer
2 Base Material KB、Shengyi、ShengyiSF305、FR408、FR408HR、IS410、FR406、GETEK、370HR、IT180A、Rogers4350、Rogers400、PTFE Laminates(Rogers series、Taconic series、Arlon series、Nelco series)、Rogers/Taconic/Arlon/Nelco laminate with FR-4 material(including partial Ro4350B hybrid laminating with FR-4)
3 PCB Type Rigid PCB/FPC/Flex-Rigid Backplane、HDI、High multi-layer blind&buried PCB、Embedded Capacitance、Embedded resistance board 、Heavy copper power PCB、Backdrill.
4 Lamination type Blind&buried via type Mechanical blind&burried vias with less than 3 times laminating Mechanical blind&burried vias with less than 2 times laminating
HDI PCB 1+n+1,1+1+n+1+1,2+n+2,3+n+3(n buried vias≤0.3mm),Laser blind via can be filling plating 1+n+1,1+1+n+1+1,2+n+2,3+n+3(n buried vias≤0.3mm),Laser blind via can be filling plating
5 Finished Board Thickness 0.2-3.2mm 3.4-7mm
6 Minimum Core Thickness 0.15mm(6mil) 0.1mm(4mil)
7 Copper Thickness Min. 1/2 OZ, Max. 4 OZ Min. 1/3 OZ, Max. 10 OZ
8 PTH Wall 20um(0.8mil) 25um(1mil)
9 Maximum Board Size 500*600mm(19”*23”) 1100*500mm(43”*19”)
10 Hole Min laser drilling size 4mil 4mil
Max laser drilling size 6mil 6mil
Max aspect ratio for Hole plate 10:1(hole diameter>8mil) 20:1
Max aspect ratio for laser via filling plating 0.9:1(Depth included copper thickness) 1:1(Depth included copper thickness)
Max aspect ratio for mechanical depth-
control drilling board(Blind hole drilling depth/blind hole size)
0.8:1(drilling tool size≥10mil) 1.3:1(drilling tool size≤8mil),1.15:1(drilling tool size≥10mil)
Min. depth of Mechanical depth-control(back drill) 8mil 8mil
Min gap between hole wall and
conductor (None blind and buried via PCB)
7mil(≤8L),9mil(10-14L),10mil(>14L) 5.5mil(≤8L),6.5mil(10-14L),7mil(>14L)
Min gap between hole wall conductor (Blind and buried via PCB) 8mil(1 times laminating),10mil(2 times laminating), 12mil(3 times laminating) 7mil(1 time laminating), 8mil(2 times laminating), 9mil(3 times laminating)
Min gab between hole wall conductor(Laser blind hole buried via PCB) 7mil(1+N+1);8mil(1+1+N+1+1 or 2+N+2) 7mil(1+N+1);8mil(1+1+N+1+1 or 2+N+2)
Min space between laser holes and conductor 6mil 5mil
Min space between hole walls in different net 10mil 10mil
Min space between hole walls in the same net 6mil(thru-hole& laser hole PCB),10mil(Mechanical blind&buried PCB) 6mil(thru-hole& laser hole PCB),10mil(Mechanical blind&buried PCB)
Min space bwteen NPTH hole walls 8mil 8mil
Hole location tolerance ±2mil ±2mil
NPTH tolerance ±2mil ±2mil
Pressfit holes tolerance ±2mil ±2mil
Countersink depth tolerance ±6mil ±6mil
Countersink hole size tolerance ±6mil ±6mil
11 Pad(ring) Min Pad size for laser drillings 10mil(for 4mil laser via),11mil(for 5mil laser via) 10mil(for 4mil laser via),11mil(for 5mil laser via)
Min Pad size for mechanical drillings 16mil(8mil drillings) 16mil(8mil drillings)
Min BGA pad size HASL:10mil, LF HASL:12mil, other surface technics are 10mil(7mil is ok for flash gold) HASL:10mil, LF HASL:12mil, other surface technics are 7mi
Pad size tolerance(BGA) ±1.5mil(pad size≤10mil);±15%(pad size>10mil) ±1.2mil(pad size≤12mil);±10%(pad size≥12mil)
12 Width/Space Internal Layer 1/2OZ:3/3mil 1/2OZ:3/3mil
1OZ: 3/4mil 1OZ: 3/4mil
2OZ: 4/5.5mil 2OZ: 4/5mil
3OZ: 5/8mil 3OZ: 5/8mil
4OZ: 6/11mil 4OZ: 6/11mil
5OZ: 7/14mil 5OZ: 7/13.5mil
6OZ: 8/16mil 6OZ: 8/15mil
7OZ: 9/19mil 7OZ: 9/18mil
8OZ: 10/22mil 8OZ: 10/21mil
9OZ: 11/25mil 9OZ: 11/24mil
10OZ: 12/28mil 10OZ: 12/27mil
External Layer 1/3OZ:3.5/4mil 1/3OZ:3/3mil
1/2OZ:3.9/4.5mil 1/2OZ:3.5/3.5mil
1OZ: 4.8/5mil 1OZ: 4.5/5mil
1.43OZ(positive):4.5/7 1.43OZ(positive):4.5/6
1.43OZ(negative ):5/8 1.43OZ(negative ):5/7
2OZ: 6/8mil 2OZ: 6/7mil
3OZ: 6/12mil 3OZ: 6/10mil
4OZ: 7.5/15mil 4OZ: 7.5/13mil
5OZ: 9/18mil 5OZ: 9/16mil
6OZ: 10/21mil 6OZ: 10/19mil
7OZ: 11/25mil 7OZ: 11/22mil
8OZ: 12/29mil 8OZ: 12/26mil
9OZ: 13/33mil 9OZ: 13/30mil
10OZ: 14/38mil 10OZ: 14/35mil
13 Dimension Tolerance Hole Position 0.08 ( 3 mils)
Conductor Width(W) 20% Deviation of Master
A/W
1mil Deviation of Master
A/W
Outline Dimension 0.15 mm ( 6 mils) 0.10 mm ( 4 mils)
Conductors & Outline
( C – O )
0.15 mm ( 6 mils) 0.13 mm ( 5 mils)
Warp and Twist 0.75% 0.50%
14 Solder Mask Max drilling tool size for via filled with Soldermask (single side) 35.4mil 35.4mil
Soldermask color Green, Black, Blue, Red, White, Yellow,Purple matte/glossy
Silkscreen color White, Black,Blue,Yellow
Max hole size for via filled with Blue glue aluminium 197mil 197mil
Finish hole size for via filled with resin  4-25.4mil  4-25.4mil
Max aspect ratio for via filled with resin board 8:1 12:1
Min width of soldermask bridge Base copper≤0.5 oz、Immersion Tin: 7.5mil(Black), 5.5mil(Other color) , 8mil( on copper area)
Base copper≤0.5 oz、Finish treatment not Immersion Tin : 5.5 mil(Black,extremity 5mil), 4mil(Other
color,extremity 3.5mil) , 8mil( on copper area
Base coppe 1 oz: 4mil(Green), 5mil(Other color) , 5.5mil(Black,extremity 5mil),8mil( on copper area)
Base copper 1.43 oz: 4mil(Green), 5.5mil(Other color) , 6mil(Black), 8mil( on copper area)
Base copper 2 oz-4 oz: 6mil, 8mil( on copper area)
15 Surface Treatment Lead free Flash gold(electroplated gold)、ENIG、Hard gold、Flash gold、HASL Lead free、OSP、ENEPIG、Soft gold、Immersion silver、Immersion Tin、ENIG+OSP,ENIG+Gold finger,Flash gold(electroplated gold)+Gold finger,Immersion silver+Gold finger,Immersion Tin+Gold finge
Leaded Leaded HASL
Aspect ratio 10:1(HASL Lead free、HASL Lead、ENIG、Immersion Tin、Immersion silver、ENEPIG);8:1(OSP)
Max finished size HASL Lead 22″*39″;HASL Lead free 22″*24″;Flash gold 24″*24″;Hard gold 24″*28″;ENIG 21″*27″;Flash gold(electroplated gold) 21″*48″;Immersion Tin 16″*21″;Immersion silver 16″*18″;OSP 24″*40″;
Min finished size HASL Lead 5″*6″;HASL Lead free 10″*10″;Flash gold 12″*16″;Hard gold 3″*3″;Flash gold(electroplated gold) 8″*10″;Immersion Tin 2″*4″;Immersion silver 2″*4″;OSP 2″*2″;
PCB thickness HASL Lead 0.6-4.0mm;HASL Lead free 0.6-4.0mm;Flash gold 1.0-3.2mm;Hard gold 0.1-5.0mm;ENIG 0.2-7.0mm;Flash gold(electroplated gold) 0.15-5.0mm;Immersion Tin 0.4-5.0mm;Immersion silver 0.4-5.0mm;OSP 0.2-6.0mm
Max high to gold finger 1.5inch
Min space between gold fingers 6mil
Min block space to gold fingers 7.5mil
16 V-Cutting Panel Size 500mm X 622 mm  ( max. ) 500mm X 800 mm ( max. )
Board Thickness 0.50 mm (20mil) min. 0.30 mm (12mil) min.
Remain Thickness 1/3 board thickness 0.40 +/-0.10mm( 16+/-4 mil )
Tolerance ±0.13 mm(5mil) ±0.1 mm(4mil)
Groove Width 0.50 mm (20mil) max. 0.38 mm (15mil) max.
Groove to Groove 20 mm (787mil) min. 10 mm (394mil) min.
Groove to Trace 0.45 mm(18mil) min. 0.38 mm(15mil) min.
17 Slot Slot size tol.L≥2W PTH Slot: L:+/-0.13(5mil) W:+/-0.08(3mil) PTH Slot: L:+/-0.10(4mil) W:+/-0.05(2mil)
NPTH slot(mm) L+/-0.10 (4mil) W:+/-0.05(2mil) NPTH slot(mm) L:+/-0.08 (3mil) W:+/-0.05(2mil)
18 Min Spacing from hole edge to hole edge 0.30-1.60 (Hole Diameter) 0.15mm(6mil) 0.10mm(4mil)
1.61-6.50 (Hole Diameter) 0.15mm(6mil) 0.13mm(5mil)
19 Min spacing between hole edge to circuitry pattern PTH hole: 0.20mm(8mil) PTH hole: 0.13mm(5mil)
NPTH hole: 0.18mm(7mil) NPTH hole: 0.10mm(4mil)
20 Image transfer Registration tol Circuit pattern vs.index hole 0.10(4mil) 0.08(3mil)
Circuit pattern vs.2nd drill hole 0.15(6mil) 0.10(4mil)
21 Registration tolerance of front/back image 0.075mm(3mil) 0.05mm(2mil)
22 Multilayers Layer-layer misregistration 4layers: 0.15mm(6mil)max. 4layers: 0.10mm(4mil) max.
6layers: 0.20mm(8mil)max. 6layers: 0.13mm(5mil) max.
8layers: 0.25mm(10mil)max. 8layers: 0.15mm(6mil) max.
Min. Spacing from Hole Edge to Innerlayer Pattern 0.225mm(9mil) 0.15mm(6mil)
Min.Spacing from Outline to Innerlayer Pattern 0.38mm(15mil) 0.225mm(9mil)
Min. board thickness 4layers:0.30mm(12mil) 4layers:0.20mm(8mil)
6layers:0.60mm(24mil) 6layers:0.50mm(20mil)
8layers:1.0mm(40mil) 8layers:0.75mm(30mil)
Board thickness tolerance 4layers:+/-0.13mm(5mil) 4layers:+/-0.10mm(4mil)
6layers:+/-0.15mm(6mil) 6layers:+/-0.13mm(5mil)
8-12 layers:+/-0.20mm (8mil) 8-12 layers:+/-0.15mm (6mil)
23 Insulation Resistance 10KΩ~20MΩ(typical:5MΩ)
24 Conductivity <50Ω(typical:25Ω)
25 Test voltage 250V
26 Impedance control ±5ohm(<50ohm), ±10%(≥50ohm)

PCBTok offers flexible shipping methods for our customers, you may choose from one of the methods below.

1. DHL

DHL offers international express services in over 220 countries.
DHL partners with PCBTok and offers very competitive rates to customers of PCBTok.
It normally takes 3-7 business days for the package to be delivered around the world.

DHL

2. UPS

UPS gets the facts and figures about the world’s largest package delivery company and one of the leading global providers of specialized transportation and logistics services.
It normally takes 3-7 business days to deliver a package to most of the addresses in the world.

UPS

3. TNT

TNT has 56,000 employees in 61 countries.
It takes 4-9 business days to deliver the packages to the hands
of our customers.

TNT

4. FedEx

FedEx offers delivery solutions for customers around the world.
It takes 4-7 business days to deliver the packages to the hands
of our customers.

FedEx

5. Air, Sea/Air, and Sea

If your order is of large volume with PCBTok, you can also choose
to ship via air, sea/air combined, and sea when necessary.
Please contact your sales representative for shipping solutions.

Note: if you need others, please contact your sales representative for shipping solutions.

You can use the following payment methods:

Telegraphic Transfer(TT): A telegraphic transfer (TT) is an electronic method of transferring funds utilized primarily for overseas wire transactions. It’s very convenient to transfer.

Bank/Wire transfer: To pay by wire transfer using your bank account, you need to visit your nearest bank branch with the wire transfer information. Your payment will be completed 3-5 business days after you have finished the money transfer.

Paypal: Pay easily, fast and secure with PayPal. many other credit and debit cards via PayPal.

Credit Card: You can pay with a credit card: Visa, Visa Electron, MasterCard, Maestro.

  • “There is only a brief wait for PCBs, and it is well worth it. The PCBTok company is highly valued. Flex, rigid, and rigid-flex boards are mass produced and prototyped expertly by this company. I will only place my PCB order with them. The store has ISO accreditation. They are excellent PCB technicians, in my opinion, and will do a fantastic job.”

    Devlin Tesca, Purchasing Specialist from Kėdainiai, Lithuania
  • “All PCB enthusiasts should give this business a shot. They might be thousands of miles away from me, but thanks to a Google search, they directed me to this location, which is wonderful! They quickly examined my schematic, which was very reassuring and prevented me from going crazy. For me, it turned out to be a quick project. Gratitude to PCBTok.”

    Thompson Cujoh, Materials Director from Newcastle, UK
  • “To evaluate the PCB project we already had, we sought the advice of PCBTok. We enquire as to its condition and request their opinion on whether or not making the necessary purchases for the multilayer board, parts, and service would be prudent. He not only saved us from a bad purchase, but also from questionable businesses. They come highly recommended from me. They are knowledgeable, skilled craftspeople who conduct themselves with integrity.”

    Dennis Gervais, PCB Inspector from Knokke Heist, Malta
Scroll to Top