How to align my tree using forest?

Question

I am trying to make a tree using forest. It is within minipage environment. But the tree does not aligns with the center of the page. Moreover I would like it if the subsequent levels too were centered around one vertical line.

\documentclass{article}
\usepackage{forest}
\usepackage{graphicx}
\usepackage{booktabs}
\usepackage{caption}
\begin{document}
\begin{minipage}{\linewidth}
\makebox[\linewidth]{
\begin{forest}
for tree={
grow'=east,draw=black,parent anchor=east,child anchor=west, align=center,
edge path={
    \noexpand\path[\forestoption{edge}]
    (!u.parent anchor) -- +(10pt,0) |- 
    (.child anchor)\forestoption{edge label};
},
}
[Microfabrication,
[Subtractive, 
[\begin{minipage}{4.5cm}{
  \begin{enumerate}
  \item \noindent $\mu$ -EDM
  \item \noindent $\mu$ -ECM
  \item \noindent LBM
  \item \noindent EBM
  \item \noindent Micro-Cutting
  \item \noindent PCM
  \end{enumerate}}
  \end{minipage}]
  ]
  [Additive
  [\begin{minipage}{4.5cm}{
  \begin{enumerate}
  \item Surface Coating
  \item Direct Writing
  \item Stereolithography
  \item Chemical \\ Deposition
  \item Polymer \\ Deposition
  \end{enumerate}}
  \end{minipage}]
  ]
  [Lithography Based
  [\begin{minipage}{4.5cm}{
  \begin{enumerate}
  \item Photolithography
  \item LIGA
  \item Soft Lithography
  \item X-Ray \\ Lithography
  \end{enumerate}}
  \end{minipage}]
  ]
  [Hybrid
  [\begin{minipage}{4.5cm}{
  \begin{enumerate}
  \item  Surface Coating
  \item  Direct Writing
  \item  Stereolithography
  \item  Chemical Deposition
  \item  Polymer Deposition
  \end{enumerate}}
  \end{minipage}]
  ]
  ]
  \end{forest}}
  \captionof{figure}{Microfabrication Techniques}
  \end{minipage}
  \end{document}

Here is the output

Answer 1

I dispensed with the minipage environment and I made it easier to handle. Also, I centered the titles and streched the boxes with the items.

\documentclass{article}
\usepackage[left=5pt,right=5pt,top=10pt,bottom=10pt]{geometry}
\usepackage{forest}
\usepackage{caption}
\newcommand{\vs}{\vspace{2mm}}

\begin{document}

\begin{figure}
\centering
\resizebox{0.9\textwidth}{!}{%
\begin{forest}
    for tree={
    child anchor=west,
    parent anchor=east,
    grow'=east, text centered,
    text width=5cm,
    draw,
    anchor=west,
    edge path={
    \noexpand\path[\forestoption{edge}]
        (.child anchor) -| +(-2pt,0) -- +(-8pt,0) |-
        (!u.parent anchor)\forestoption{edge label};
            },
    }
    [\centering Microfabrication
        [{Subtractive}
            [{\begin{enumerate}
                \item $\mu$ -EDM
                \item $\mu$ -ECM
                \item LBM
                \item EBM
                \item Micro-Cutting
                \item PCM
            \end{enumerate}}\vs
        ]
    ]
    [Additive
            [{\begin{enumerate}
                \item Surface Coating
                \item Direct Writing
                \item Stereolithography
                \item Chemical Deposition
                \item Polymer Deposition
            \end{enumerate}}\vs
        ]
    ] 
    [Lithography Based
            [{\begin{enumerate}
                \item Photolithography
                \item LIGA
                \item Soft Lithography
                \item X-Ray Lithography
            \end{enumerate}}\vs
        ]
    ]
    [Hybrid
            [{\begin{enumerate}
                \item  Surface Coating
                \item  Direct Writing
                \item  Stereolithography
                \item  Chemical Deposition
                \item  Polymer Deposition
            \end{enumerate}}\vs
        ]
    ]
]
\end{forest}}
\caption{Microfabrication Techniques}
\end{figure}
\end{document}

Answer 2

like this?

nodes with lists are horizontally aligned with forest option tier/.pgfmath=level(). for list is employed enumitem package. instead minipage in nodes with lists is used forest option where n children=0{text width=4cm}{},:

\documentclass{article}
\usepackage[edges]{forest}
\usepackage{enumitem}
\usepackage{caption}

\begin{document}
    \begin{figure}[ht]
    \setlist{nosep, leftmargin=*, before= \vspace{-0.5\baselineskip}}
    \centering
\begin{forest}
  for tree={
    draw=black,
    where n children=0{text width=4cm}{},   % <---
    grow'=0,
    l sep=2em,                  
    forked edge,
    fork sep=1em,                           % <---
    anchor=west,
    tier/.pgfmath=level(),                  % <---
    },
[Microfabrication
 [Subtractive
  [\begin{enumerate}                        % no minipage
    \item $\mu$ -EDM
    \item $\mu$ -ECM
    \item LBM
    \item EBM
    \item Micro-Cutting
    \item PCM
   \end{enumerate}]
  ]
 [Additive
  [\begin{enumerate}
    \item Surface Coating
    \item Direct Writing
    \item Stereolithography
    \item Chemical Deposition
    \item Polymer Deposition
   \end{enumerate}]
  ]
 [Lithography Based
  [\begin{enumerate}
    \item Photolithography
    \item LIGA
    \item Soft Lithography
    \item X-Ray Lithography
   \end{enumerate}]
  ]
  [Hybrid
  [\begin{enumerate}
    \item  Surface Coating
    \item  Direct Writing
    \item  Stereolithography
    \item  Chemical Deposition
    \item  Polymer Deposition
   \end{enumerate}]
   ]
 ]
\end{forest}
  \caption{Microfabrication Techniques}
  \label{fig:forest}
    \end{figure}
\end{document}

addendum (1): if you more like to have equal width of all nodes in forest, then for for tree options use the following:

  for tree={
    draw=black,
    text width=38mm,                         % <---
    text centered,                           % <---
    grow'=0,
    l sep=2em,
    forked edge,
    fork sep=1em,                           
    anchor=west,
    },

and you will obtain:

in comparison with your mwe i put image in float environment figure with option [ht] which ensure that diagram will be in text where is inserted, if on page is enough place for it or in opposite case on the top of the next page.

addendum (2):

one more example (just for exercise). with for tree options:

  for tree={
    draw=black,
    where n children=1{text width=2cm, text centered}{},  % <---
    where n children=0{text width=4cm}{},                 % <---
    grow'=0,
    l sep=2em,
    forked edge,
    fork sep=1em,
    anchor=west,
    },

you will obtain: