Question about density unit in cgs

Hi,

When I was using the si unit system, the simulation can run without error. However, when I want to change to cgs unit system and convert the density constant from 2500 to 2.5, there is an error saying "Mesh elements have been lost / left the domain". When I set the density constant to 2500 the error is fixed.

So, I am wondering what is the unit for density constant in cgs system?

Here is my input script.
# Moving mesh example

atom_style granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes
units cgs

#region
region reg block -0 1.0 -0.0 10.0 -0.0 2.0 units box
create_box 1 reg

neighbor 0.05 bin
neigh_modify delay 0

#Material properties
fix m1 all property/global youngsModulus peratomtype 2.3e8
fix m2 all property/global poissonsRatio peratomtype 0.4
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.9
fix m4 all property/global coefficientFriction peratomtypepair 1 0.05
fix m5 all property/global characteristicVelocity scalar 2.
fix m6 all property/global cohesionEnergyDensity peratomtypepair 1 300
#fix m7 all property/global coefficientRollingFriction peratomtypepair 1

#pair style
pair_style gran model hertz tangential history cohesion sjkr #Hertzian with cohesion
pair_coeff * *

timestep 0.00001

fix integr all nve/sphere
fix gravi all gravity 981 vector 0.0 0.0 -1.0

#box walls
fix boxwalls_x1 all wall/gran model hertz tangential history primitive type 1 xplane -0.0
fix boxwalls_x2 all wall/gran model hertz tangential history primitive type 1 xplane +1.0
fix boxwalls_y1 all wall/gran model hertz tangential history primitive type 1 yplane -0.0
fix boxwalls_y2 all wall/gran model hertz tangential history primitive type 1 yplane +10.0
fix boxwalls_z1 all wall/gran model hertz tangential history primitive type 1 zplane -0.0
fix boxwalls_z2 all wall/gran model hertz tangential history primitive type 1 zplane +2.0

#import mesh from cad:
fix cad1 all mesh/surface file bed1.stl type 1
fix cad2 all mesh/surface file bed2.stl type 1
fix cad3 all mesh/surface file bed3.stl type 1
fix feedstock all mesh/surface/stress file feedstock.stl type 1
fix platform all mesh/surface/stress file platform.stl type 1
fix roller all mesh/surface/stress file roller.stl type 1

fix granwalls all wall/gran model hertz tangential history cohesion sjkr mesh n_meshes 6 meshes cad1 cad2 cad3 feedstock platform roller
#region of insertion
region bc block 0 1 1 4 0.5 1.2 units box

#particle distributions
fix pts1 all particletemplate/sphere 15485863 atom_type 1 density constant 3900 radius constant 0.004
fix pdd1 all particledistribution/discrete 15485867 1 pts1 1.0

fix ins all insert/pack seed 32452843 distributiontemplate pdd1 vel constant 0. 0. 8 &
insert_every once overlapcheck yes all_in yes particles_in_region 1000 region bc

#thermo settings
compute 1 all erotate/sphere
thermo_style custom step atoms ke c_1 vol
thermo 1000
thermo_modify lost ignore norm no

#make a dump of particles and the stl file
dump dmp all custom/vtk 200 post/movingMesh_*.vtk id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
#dump dumpstress all mesh/gran/VTK 200 post/mesh_*.vtk stress wear roller
dump dumpstl all mesh/stl 200 post/dump*.stl

#run with particle insertion

run 2000 upto
unfix ins

#run to let particle settle
run 50000 upto

#moving platform
fix moveplatform all move/mesh mesh platform linear 0 0. -10.0
run 50100 upto
unfix moveplatform

#moving feedstock
fix movefeedstock all move/mesh mesh feedstock linear 0 0. 10.0
run 55100 upto
unfix movefeedstock

#run to let particle settle
run 50000

#now spread

fix moveroller all move/mesh mesh roller linear 0 10. 0
run 80000

Thanks ,
Mill