PCB / Lay-up and lamination

Bare board · 03

Lay-up and lamination

Cores and prepreg are stacked and pressed into one multilayer panel. Thickness and warp are set here.

01 What happens

  • Inner cores, prepreg and copper foil are stacked to the agreed stack-up, then pressed under heat and vacuum.
  • The press cycle sets final thickness, resin fill and how well inner copper is buried.
  • After press the panel is trimmed and target holes are drilled or punched for later registration.

02 On an ESP32 board

  • 1.6 mm is common for ESP32 DevKit-class boards; 0.8 mm is used in tight enclosures and warps more in reflow.
  • Odd stack-ups (asymmetric copper) bow. Keep copper balance if the board is long and thin.
  • Antenna keep-out is a copper drawing issue, but a resin-rich thin board also changes dielectric under the antenna.

03 What usually fails

  • Delamination, voids, or wrinkle in inner copper.
  • Thickness out of spec — connectors and shields no longer sit.
  • Mis-registered cores so later drills miss inner pads.

04 What we check

  • We put finished thickness, copper weight and Tg on the fab note, especially for lead-free reflow.
  • For a first ESP32 article we prefer a standard 1.6 mm 4-layer or 2-layer stack unless the enclosure forbids it.

← Previous step: Inner layer image and etchNext step: Drilling →

中文

PCB工艺 / 叠层与压合

光板 · 03

叠层与压合

芯板和半固化片压成多层板。板厚和翘曲在这里定下来。

01 这一步做什么

  • 按叠层把内层、半固化片和铜箔叠好，加热真空压合。
  • 压合周期决定成品厚度、填胶，以及内层铜埋得实不实。
  • 压完裁边，打靶孔给后面钻孔对位。

02 落到 ESP32 板上

  • ESP32 开发板一类常用 1.6 mm；壳很紧时用 0.8 mm，回流时更容易翘。
  • 铜厚不对称会长弯。又长又薄的板更要铜平衡。
  • 天线净空是铺铜问题，树脂多、板又薄时，天线底下的介质也会变。

03 常见失败

  • 分层、空洞、内层皱铜。
  • 厚度超差，连接器和屏蔽罩对不上。
  • 芯板对位偏，后面钻孔打不中内层盘。

04 我们查什么

  • 工艺备注写清成品厚度、铜厚、Tg，尤其无铅回流。
  • 第一次做 ESP32 样，除非外壳限制，优先常规 1.6 mm 两层或四层。

← 上一步: 内层图形与蚀刻下一步: 钻孔 →