I shall be fabricating a fixed gantry cnc milling machine over
coming weeks along with a blast furnace, i have done a bit of
reading here on CNCZone so i thought i would also do a worklog
here too :-)
The plan is to construct a milling machine that will shape construction
foam, this foam will be used in 'lost foam metal casting' For those
unfamiliar with this metal casting technique and are curious as to
how it works my mate Frank has an excellent write up on his web site
Frank has kindly sent me 3 stepper motors (still in transit) and the
controller board to run the motors free of charge. I am also loosely
basing my mill design on one of Franks first mills
OK..so you know what is being made and why, now the how...
MDF and Plexi, 15mm solid steel rod, 1/2in threaded rod ~40
sealed bearings and few hundred screws and bolts 3 stepper
motors and PC PSU will be used to construct the mill.
I have also decided this mill will be used not only to shape the
foam for metal casting but to mill solid billet aluminum THUS
this mill will be reinforced ALOT more than mill used solely
for foam/wood/plastic....etc milling jobs.
I purchased a 1200x1100 sheet of 18mm MDF from Bunnings for
~$32 on the weekend, along with a few hundred screws and MDF
glue. The first part of the construction will be the base. The base
will support the gantry and house the slides for the 'X' axis table.
he Gantry will have the 'Y' and 'Z' axis.
I have decided on a 650 watt Ozito router for the 'engine' of this
(threaded rods in pic WILL NOT be the ones used in the mill)
I have started 'doubling up' the mdf to make a 36mm thick sides
for the base.Here's a few pics of the beginnings of this mill-->
The MDF was cut to length, MDF glue is spread on the pieces
before they are screwed together to form a solid side-->
Once all 4 sides have been constructed i cut MDF to size for a base-->
As this mill will be used for aluminum it will need to be
very sturdy, i have started adding supports to the base,
there will be 6 more to be added to the sides along with
the 8 already installed-->
The base measures 800mm x 730mm... The table will slide
enough for me to pop in a PC case side to cut windows
and also 'etch' a design on the plex, this was actually
my main reason for making it this large, initially i was
going to make it ~600x400mm.
Once the construction of the base and gantry are complete i
will seal the entire unit with shellac prior to coating it with
Silver Hammer tone paint. The table housing for 'z' axis will
be constructed entirely of acrylic plexi/aluminium I also intend having a dust extraction unit attached to the head of the mill to remove foam when foam
is being shaped.
progress on this project should be quite regular as i have the
majority of the parts to construct the mill. Things i still need
are bearings...the slides for the 'x' 'y' and 'z' axis require 12
sealed bearings each.
The days objective of completing the gantry for the mill was achieved, here's a few pics of the days work-->
The Gantry side 'pillars'
I cut these to size prior to drilling/gluing and screwing
Side pillars complete (these will NOT be fastened to the lower base till all axis are complete so as i can move gantry to exact position to center tool bit)
Top panels were cut/drilled/glued/screwed
Sort of taking shape...to someone who knows whats being built...and has a vivid imagination ahaha
Bearings & linear carriages
I went for 16mm OD 8mmID 5mm wide
bearings which i came across on EBay. Here's the lot i bought today
With luck they will be here mid next week as they are
in Australia and i was able to do a bank transfer, if i bought
the bulk lot skate bearings it would have taken 5-7 days
just to organize the $$$ into my PayPal account (i have no CC)
then another 2 weeks wait for them to ship from USA :-S
My original idea for the linear carriages was to utilize
angle iron positioned in a 'V' orientation with bearings
attached to the sides, the bearings would run on round
bar which i have a heap of here...NOW, i have
changed this plan seeing the OD of the bearings i will
be using is smaller than the skate bearings, the smaller
bearing wooould work, but using bolts to fasten
them wouldnt be an option, i would have to use threaded
rod and weld the rod directly to the angle instead of
popping a bolt through a hole, its just a lot of farting
about, the new carriage i can cut all parts on the table
saw and bolt everything together neatly and quickly with
off the shelf fasteners.....i quickly sketched up a new
Linear Carriage design that will run on a square
rail, I can pick up 25mmx25mm square tube with 3.2
wall thickness for 50 bucks for 6m length this will do
niiicely for the mill rails so this will be the direction i
shall roll in...
Linear Carriage Design
Apologies no flash AutoCAD here just pen and paper for now LoL
After i had finished the sketch i thought the design
could be improved further by adding additional bearings
where the adjustment nuts are. I will use white acrylic
perspex (same stuff you see the cutting boards
made of...), for the carriages and this material
would indeed slide fine on the rails without bearings, but i guess over time
it would wear also and cause some slop...so bearings will
be popped in to address this issue :-)
Rain kept up all day (still raining now) so i stayed in and
got no further with the mill, hopefully better weather
tomorrow and i shall venture out for some supplies
(bondo and another can of Hammertone paint)
so i can continue on with mill fab.
i have no idea when it comes to anything more complicated than changing batteries in my keyboard hehe...
I wasn't able to get anything done over the weekend i
was away at my brothers helping panel beat/sand his car
Saturday and out with mates Sunday. I did manage
to pick up a $10.00 tub of body filler from SuperCheap Autos
though and today got a start on filling the countersunk
I Had finished sanding the sides and the bottom of the base
before running out of sanding pads, thought i would splash
on a coat of Hammertone Paint on the base, i need another
tin thats all i had left from another project...I like the durability
of this stuff its freaking tuff as nails, the finish is neat too IMO.
Will be off to Bunnings(harware store here in Australia) tomorrow for more supplies, will also hit up the Scrap Metal Merchants and see if i can scrounge some suitable box tube for the rails IF NOT...i can purchase a length
(6m) for $50ish new from Metal Corp...either way though i may
have issues getting it home this week as my buddy with the ute is
house sitting the other side of town and I wont be paying 60 bucks
for delivery :-S ...I'll see if i can get the length cut to 1.5m and have a
wheelchair taxi pickz me up will fit the steel in no worries hehee..
they are hard to get hold of on short notice at times though...
seez how we go.(i usually take normal sedan/wagon taxi my
wheelchair is foldup sports job)
Back with more soon fellas..