4 Layer Medium Run Service

Moving to a small production run? Our medium run service will help bridge the gap between prototypes and a full panel.


$2 per square inch, 150 square inch minimum. You can have as many different designs as you want, as long as each design is ordered in a multiple of 3 boards.

For example, if you two 25 square inch designs, you could order 3 of each for a total cost of $300.

150 inches is just the minimum order. You can order as much as you’d like beyond that.

Turn Times

Fabrication time can vary for medium run orders. Boards typically ship within 14 calendar days but may take up 4 weeks.

To make an order, please contact support@oshpark.com.

We do not offer Super Swift Service for 4 layer boards.

For faster options, you may be interested in our Standard 4 Layer Service.

Fabrication Specs

4 Layer PCB Specs

Quick Specs

Detailed Specs

4 Layer Stackup

The current 4 layer board stackup is as follows:

Thickness Layer Tolerance
1 mil solder resist +/-0.2mil
1.4 mil 1 oz copper  
6.7 mil FR408 prepreg +/-.67mil
0.7 mil 0.5 oz copper  
47 mil FR408 core +/-4.7mil
0.7 mil 0.5 oz copper  
6.7 mil FR408 prepreg +/-.67mil
1.4 mil 1 oz copper  
1 mil solder resist +/-0.2mil

The substrate for both the core and prepreg is FR408, with a dielectric constant of 3.66 at 1GHz, and is compatible with a lead free process. The boards themselves are also lead free and RoHS compliant.

Layer Naming

When sent to fabrication, the layers are manufactured in the following order according to their file extension. We advise following this naming scheme if your design is sensitive to distance of the inner planes in order to avoid any confusion.

Layer Suggested File Extension  
Layer 1 .GTL Top or Front layer
Layer 2 .G2L Internal plane
Layer 3 .G3L Internal plane
Layer 4 .GBL Bottom or Back layer

Internal Plane Polarity

When submitting gerbers, we need the “positive” internal planes, meaning that lines represent copper, not the absence of copper.

Some CAD tools will generate the internal planes as power planes with “negative” polarity so the lines indicate where copper should be removed. To work around this, declare the internal planes as signal layers and use a copper pour to define the power plane.

Take a look at our Positive and Negative Gerbers page for more information.

4 Layer Drill Specs

Spec Size
Minimum annular ring 4 mil
Minimum hole size 10mil
Maximum plated hole size 260 mil
Maximum non-plated hole size None
Via plating thickness 1mil
Blind Vias No
Buried Vias No