Your is not a proper way for builder pattern in PHP. Here is the example for Builder pattern in PHP,
* The Builder interface specifies methods for creating the different parts of
* the Product objects.
public function producePartA(): void;
public function ...
The Other Builder Pattern
First, let me just briefly mention that there's a different pattern under the same name: Joshua Bloch's Builder pattern described in Effective Java (see the excerpt here). This pattern was inspired by the GoF Builder pattern; however, it's purpose/intent is not the same - it solves a different problem, so, despite what that ...