Roboticus@Waubli ~
$ cat t.pl
use strict;
use warnings;

# The data
my @recs = (
    [ 'MM_MM_STD_gate', 152.401574, -22.047244, 'mils',
                        3871.0, -560.0, 'microns' ],
    [ 'RFN_a',          337.244094,  0.787402,  'mils',
                        8566.0, 20.0, 'microns' ],
    [ 'RFN_b',          366.181102,  0.787402,  'mils',
                        9301.0, 20.0, 'microns' ],
    [ 'RFN_c',          376.929133,  0.787402,  'mils',
                        9574.0, 20.0, 'microns' ],
    [ 'MM_STD2_gate',   -259.488188,  -22.047244,  'mils',
                        -6591.0, -560.0, 'microns' ],
    [ 'RBASE_right_2',  -366.181102,  -33.464566,  'mils',
                        -9301.0, -850.0, 'microns' ],
);

print "\n------ Report1: (printf) ------\n\n";

# I made it easy on myself by *not* using the fake field here so I could
# just print the data by expanding the data in-line in the printf statement.
my $fmt = "%-13s % 24f %-14f %-4s\n"
. "              %24.6f %-14f %-4s\n";

for my $ar (@recs) {
    printf $fmt, @$ar;
}

print "\n\n------ Report 2 (Named formats) ------\n\n";

# The format statement embeds the variables to map to the fields inline, so
# the variable must already be declared
my $ar;

# Define the format visually, along with the variables to stuff into them
format DETAIL =
@<<<<<<<<<<<<  @####.##### @###.###### @<<<<<<<<<
$ar->[0],      $ar->[1],   $ar->[2],   $ar->[3],
               @####.##### @###.###### @<<<<<<<<<
               $ar->[4],   $ar->[5],   $ar->[6];
.

# Specify the format type to use for each write statement (you can have
# multiple formats and switch between them as needed).
select(STDOUT);
$~ = "DETAIL";

# Print the report
for $ar (@recs) {
    write;
}

Roboticus@Waubli ~
$ perl t.pl

------ Report1: (printf) ------

MM_MM_STD_gate               152.401574 -22.047244     mils
                           3871.000000 -560.000000    microns
RFN_a                       337.244094 0.787402       mils
                           8566.000000 20.000000      microns
RFN_b                       366.181102 0.787402       mils
                           9301.000000 20.000000      microns
RFN_c                       376.929133 0.787402       mils
                           9574.000000 20.000000      microns
MM_STD2_gate               -259.488188 -22.047244     mils
                          -6591.000000 -560.000000    microns
RBASE_right_2              -366.181102 -33.464566     mils
                          -9301.000000 -850.000000    microns


------ Report 2 (Named formats) ------

MM_MM_STD_gat    152.40157  -22.047244 mils
                3871.00000 -560.000000 microns
RFN_a            337.24409    0.787402 mils
                8566.00000   20.000000 microns
RFN_b            366.18110    0.787402 mils
                9301.00000   20.000000 microns
RFN_c            376.92913    0.787402 mils
                9574.00000   20.000000 microns
MM_STD2_gate    -259.48819  -22.047244 mils
               -6591.00000 -560.000000 microns
RBASE_right_2   -366.18110  -33.464566 mils
               -9301.00000 -850.000000 microns