# Horizontally centre a table

any idea on how to horizontally center this Table within the page? Thank you very much. Regards.

\setlength\tabcolsep{4pt}
\setlength\extrarowheight{5pt}
\begin{table}[]
\centering
\caption{Fibre architecture of thermoplastic micro-fibre veils used for mode-I interlaminar fracture toughness testing (for the corresponding $G$\textsubscript{IC} results refer to Table \ref{table:veils2}). \textcolor{red}{centrar}}
\label{table:veils1}
\begin{threeparttable}
\makebox[\textwidth]{%
\begin{tabular}{ *{6}{c} }
\toprule
Reference         & Laminate      & Veil      & $\bar{\beta}$ (g/m\textsuperscript{2})     & $\omega$ ($\micro$m)      & $\rho$ (g/m\textsuperscript{3})\tnote{1} \\
\midrule
Kuwata \cite{Kuwata2011, Kuwata2011a} & \makecell{Carbon/epoxy (non-crimp \\ and plain-weave fabrics)} & \mr{CoPA} & \mr{21} & \mr{59} & 1.14 \\
&   \makecell{Carbon/vynil ester (non- \\  crimp and plain-weave fabrics)}     &        &        &        &   \\
Barjasteh \cite{Barjasteh2017} & Carbon/benzoxazine & PA12 & 12 & 17\tnote{2} & 1.25 \\
Saz-Orozco \cite{Saz-Orozco2015} & Glass/vynil ester & PA66 & 17 & 25 & 1.14 \\
O'Donovan \cite{ODonovan2014} & Glass/polyester & PA66 & 9 & 11.5 & 1.32 \\
Ramírez \cite{Ramirez2015} & Carbon/epoxy & PEEK & 9 & 11.5 & 1.32 \\
Ni \cite{Ni2015} & Carbon/epoxy & Aramid & 16 & 15 & 1.44 \\
\mr{Kuwata \cite{Kuwata2011, Kuwata2011a}} & Carbon/epoxy & \mr{CoPE} & \mr{23} & \mr{12} & \mr{1.38} \\
& Carbon/vynil ester & & & & \\
Wong \cite{Wong2017} & Carbon/epoxy & Kevlar & 26 & 12 & 1.44 \\
Fitzmaurize \cite{Fitzmaurice2016} & Glass/polyester & PET & 45 & 20 & 1.41 \\
Saz-Orozco \cite{Saz-Orozco2015} & Glass/vynil ester & PET & 45 & 20 & 1.41 \\
\mr{Beylergil \cite{Beylergil2018}} & \mr{Carbon/epoxy} & \mr{PA66} & 17 & \mr{19.90} & \mr{1.14} \\
& & & 50 & & \\
Ramírez \cite{Ramirez2015} & Carbon/epoxy & PPS & 7 to 35 & 10 & 1.30 \\
& & & 8 to 22 & 14 & \\
\bottomrule
\end{tabular}}
\begin{tablenotes}\footnotesize
\item[2] taken from \cite{matweb, polymer_handbook}
\item[2] measured from a picture in \cite{Barjasteh2017}
\end{tablenotes}
\end{threeparttable}
\end{table}

• Vertically or horizontally centre? – Bernard Apr 17 at 8:54
• Horizontally, sorry. – Santi Apr 17 at 9:09
• You already coded \centering, which centres the table between the margins. Beware that the default left and right margins are no equal. – Bernard Apr 17 at 9:13
• add \usepackage[showframe]{geometry} to your document to see that your table is already centered – def Apr 17 at 9:21
• How is the \mr macro defined? – Mico Apr 17 at 9:30

You're not using the syntax of the threeparttable environment correctly: The \caption statement, when present, must be inside the threeparttable matter.

I would simplify the table layout by switching to a tabularx environment and letting the width of the second column adjust, as needed, so that the width of the full table is equal to \textwidth.

In addition, I would impose a bit more structure on the material in the table header, and I would use the \si macro (provided by the siunitx package) to typeset scientific units.

Finally, I had to make a guess as to how \mr is defined. I wouldn't be surprised at all if the guess isn't correct.

\documentclass[10pt]{article}
\usepackage[T1]{fontenc}
\usepackage{newtxtext,newtxmath} % optional (Times Roman font)
\usepackage[flushleft]{threeparttable}
\usepackage{tabularx,ragged2e,booktabs,siunitx}
\newcolumntype{L}{>{\RaggedRight\arraybackslash}X}
\newcommand\mr[1]{#1} % ???
\begin{document}

\begin{table}
\setlength\tabcolsep{4pt}
\setlength\extrarowheight{2pt}
\sisetup{per-mode=symbol}
\begin{threeparttable}
\caption{Fibre architecture of thermoplastic micro-fibre veils used for \mbox{mode-I} interlaminar fracture toughness testing.
(For the corresponding $G$\textsubscript{IC} results refer to Table~\ref{table:veils2}.)}
\label{table:veils1}
\begin{tabularx}{\textwidth}{@{} lLl *{3}{c} @{}}
\toprule
Reference & Laminate & Veil & $\bar{\beta}$ & $\omega$ & $\rho$\tnote{1}  \\
& & & (\si{\gram\per\meter\squared}) & (\si{\micro\meter}) & (\si{\gram\per\meter\cubed}) \\
\midrule
Kuwata \cite{Kuwata2011, Kuwata2011a}
& Carbon/epoxy (non-crimp and plain-weave fabrics)
& \mr{CoPA} & \mr{21} & \mr{59} & 1.14 \\
&  Carbon/vynil ester (non-crimp and plain-weave fabrics)
&        &        &        &   \\
Barjasteh \cite{Barjasteh2017} & Carbon/benzoxazine & PA12 & 12 & 17\tnote{2} & 1.25 \\
Saz-Orozco \cite{Saz-Orozco2015} & Glass/vynil ester & PA66 & 17 & 25 & 1.14 \\
O'Donovan \cite{ODonovan2014} & Glass/polyester & PA66 & 9 & 11.5 & 1.32 \\
Ramírez \cite{Ramirez2015} & Carbon/epoxy & PEEK & 9 & 11.5 & 1.32 \\
Ni \cite{Ni2015} & Carbon/epoxy & Aramid & 16 & 15 & 1.44 \\
\mr{Kuwata \cite{Kuwata2011, Kuwata2011a}} & Carbon/epoxy & \mr{CoPE} & \mr{23} & \mr{12} & \mr{1.38} \\
& Carbon/vynil ester & & & & \\
Wong \cite{Wong2017} & Carbon/epoxy & Kevlar & 26 & 12 & 1.44 \\
Fitzmaurize \cite{Fitzmaurice2016} & Glass/polyester & PET & 45 & 20 & 1.41 \\
Saz-Orozco \cite{Saz-Orozco2015} & Glass/vynil ester & PET & 45 & 20 & 1.41 \\
\mr{Beylergil \cite{Beylergil2018}} & \mr{Carbon/epoxy} & \mr{PA66} & 17 & \mr{19.90} & \mr{1.14} \\
& & & 50 & & \\
Ramírez \cite{Ramirez2015} & Carbon/epoxy & PPS & 7 to 35 & 10 & 1.30 \\
& & & 8 to 22 & 14 & \\
\bottomrule
\end{tabularx}

\smallskip\footnotesize
\begin{tablenotes}
\item[1] taken from \cite{matweb, polymer_handbook}
\item[2] measured from a picture in \cite{Barjasteh2017}
\end{tablenotes}
\end{threeparttable}
\end{table}
\end{document}