ACF Support: http://support.advancedcustomfields.com/forums/topic/orderby-title-instead-of-foreach/#post-4211

acf.php

<?php if ( get_field( 'schede_prodotti' ) ): ?>
<table class="product-list simple-list">
    <?php

        $ids   = array(); // Empty array for the $post->IDs from the relationship fields
        $files = array(); // Empty array for the files from the repeater fields

        while( has_sub_field( 'schede_prodotti' ) ):

            /**
             * Get the IDs
             *
             * Returns an array of the IDs of the posts
             * selected using the Relationship field.
             *
             * @var array
             */
            $id    = get_sub_field( 'relazione_prodotti' );
            $ids[] = $id[0]; // We need the first array of the return value of the relationship field

            /**
             * Get the files
             *
             * Store the files under the $post->ID from the relationship field
             * and use the field name for reference.
             *
             * @var $array
             */
            $files[$id[0]]['scheda_tecnica'] = get_sub_field('scheda_tecnica');
            $files[$id[0]]['scheda_di_sicurezza'] = get_sub_field('scheda_di_sicurezza');

        endwhile; // has_sub_field( 'schede_prodotti' )

        if ( $ids ) : // Check if we have $ids from the posts.

            /**
             * Prepare the get_posts arguments
             *
             * With the 'orderby' => 'ttile' we accomplish the goal of having the
             * products ordered by name instead of drag and drop.
             *
             * @see http://codex.wordpress.org/Template_Tags/get_posts#Parameters
             * @var array
             */
            $args = array(
                'post__in'  => $ids,        // Use the ids from above
                'order'     => 'ASC',       // Order
                'orderby'   => 'title',     // Field to order the posts by
                'post_type' => 'prodotti'   // The custom post type you use
            );

            /**
             * Query the Posts
             *
             * @var array
             */
            $posts = get_posts( $args );

            if ( $posts ) : // Check if we have $posts

                foreach ( $posts as $post ) : setup_postdata( $post ); ?>
                    <tr>
                        <td class="title">
                            <span><?php the_title(); ?></span>
                        </td>
                        <td>
                            <a href="<?php echo $files[$post->ID]['scheda_tecnica']; ?>" class="notifiche" data-tipo="Scheda Tecnica">Scarica la Scheda Tecnica</a>
                        </td>
                        <td>
                            <a href="<?php echo $files[$post->ID]['scheda_di_sicurezza']; ?>" class="notifiche" data-tipo="Scheda di Sicurezza">Scarica la Scheda di Sicurezza</a>
                        </td>
                    </tr><?php

                endforeach; // ( $posts as $post )
                wp_reset_postdata();

            endif; // ( $posts )
        endif; // ( $ids )
    ?>
</table>
<?php endif; // get_field( 'schede_prodotti' ) ?>