# Problem with horizontal alignment in minipage environment

This may be a very stupid question, but it is driving me crazy.

I have three tcolorbox linked by arrows. The second line of boxes are in a minipage environment, and I want one flushleft and one in the center below the first box.

This is my code:

\begin{center}
\begin{tcolorbox}[enhanced, overlay, width=1.5in, halign = flush center, remember as=ci]
Circuit Imprimé
\end{tcolorbox}

\begin{minipage}{.5\linewidth}
\begin{flushleft}
\begin{tcolorbox}[enhanced, overlay, width=1.3in, halign = flush center, remember as=pm]
Procédés\\ Métallurgiques
\end{tcolorbox}
\end{flushleft}
\end{minipage}%
\begin{minipage}{.3\linewidth}
\begin{tcolorbox}[enhanced, overlay, width=1.8in, halign = flush center, remember as=adm]
Analyse des matériaux
\end{tcolorbox}
\end{minipage}

\end{center}

\begin{tikzpicture}[overlay,remember picture,line width=0.5mm,draw=red!75!black]
\draw[->, rounded corners] (ci.east) -- ++(1.5,0)  |- (adm.east);
\end{tikzpicture}
\begin{tikzpicture}[overlay,remember picture,line width=0.5mm,draw=red!75!black]
\draw[->, rounded corners] (adm.west) to (pm.east);
\end{tikzpicture}


But i get something like this:

EDIT: To be honest I am trying to redo this chart for a project, in a more stylised manner. But since I'm new to tikz and tcolorbox, it's no super easy:

• The problem is to small offset for arrows, see my answer below. – Zarko Feb 5 '16 at 3:13

Your tikzpicures replace width:

\begin{tikzpicture}[overlay,remember picture,
line width=0.5mm, draw=red!75!black,
rounded corners]
\draw[->] (ci.east) -- +(5,0)  |- (adm);
\end{tikzpicture}


and you will get:

I wonder, why you draw this image on so complicated way, directly in TikZ it would be far more simple and under "control":

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,positioning}
\usepackage[many]{tcolorbox}

\begin{document}
\begin{tikzpicture}[
node distance = 5mm and -3mm,
mynode/.style = {draw=gray, ultra thick, fill=gray!20,
rounded corners, align=center,
minimum height= 12mm, inner sep=2mm,
text width = #1},
arrow/.style = {draw=red!75!black, line width=1mm,
-{Triangle[]}  }
]
\node (ci)  [mynode=1.5in]      {Circuit Imprimé};
\node (pm)  [mynode=1.3in,
below  left=of ci] {Procédés\\ Métallurgiques};
below right=of ci] {Analyse\\ des Matériaux};
%
\draw[arrow] (ci.east) -- +(5,0) |- (adm);

As can you see, above solution no need minipages, content of tcolorbox-es you is written into node, node are positioned relatively to each other. Distance is controlled by node distance. Only car is to determine ofset of arrow between nodes ci and adm.
Note, at first images I didn't use utf8 coding, so some letters are missing.
• Added image in your question even more convinced me, that you need to draw image! The left border of this image is depend on how it is included into your text. If it should start at left border of text, than don't use center environment! Added picture shows (as I see) , decision tree. See texample.net for more examples, how to do this. Anyway, in the first part of my answer I provide solution for your temporary way of drawing picture. Withit, I'm sure so, your original wuestion is solved. For new images, I suggest you ask a new question. – Zarko Feb 5 '16 at 5:32