The wife and I may have fallen into a good thing... She got a lead about a
local developer that needs a WHOLE MESS of architectural WW and trim for a
subdivision of about 90 new Victorian style homes. This would entail doing
custom gingerbread, corbels, trim, fencing and accent pieces. He wants the
work done out of a new non-wood composite called Azek (www.azek.com) and was
asking about CNC for increased production speed.
The open question for the moment is how much, how fast. If he is going to
need 5's & 10's of things and the like, a home built router duplicator might
be the most time/materials/cost/profit effective. If he's going to need the
lot of them - hundreds of elements, then perhaps CNC might be the way to go.
I freely admit I don't yet have all of the answers.
I've looked at shop bot (www.shopbottools.com) but don't know what to make
of the software issues. Do any of you have woodworking CNC or Duplicator
experience? What are the thresholds for moving up from duplication to CNC?
SWMBO is going to do some consulting work for him for color selections and
trim suggestions. After that, his first phase is 14 units, the subdivision
entrance and models.
This could *really* work out well in supplementing what we are already
doing. If we did go with CNC, we would have to put the unit out at her
dad's metal fabrication shop, because we just don't have the room. I would
appreciate any practical tips, what to look for and perhaps most
importantly, what to avoid in checking all of this out.
Thanks in advance,
Strange - I'm thinking the same thing. I wonder if it's just the "you
want what you can't have syndrome". I don't think so though, as I
skip over the vast majority of the threads here and this was one of
the 10% or so I actually looked at.
Well! Guess you told me :-)
here it is:
I have a shopbot in my garage ... actually my boss has his shopbot in my
garage ... but I've put several hundred hours cutting time on it since last
February and can share some of my experiences with you.
I've dedicated 1/2 of my 20 x 22 foot garage for the shopbot and the dust
collector system. It's a bit tight, but workable. You'll also need space for
your uncut stock and your finished parts.
Software: The shopbot comes with an entry-level program (Part Wizard) to
create or convert cad drawings into shopbot patterns. This gives you 2-1/2
D, in that you must set the depth (z-axis) manually. Thus, if you're trying
to do a three-dimensional part with many gradient changes, you'll not do it
with the supplied software. There are upgrades and other packages that will
handle 3-D ... and you can get an accessory probe that will map an existing
3-D object to duplicate it.
If you're working with flat shapes ... fixed thicknesses ... and only need
two to 5 depths, the supplied software will work just fine. What I do is
flatten out a 3-D CAD drawing to 2-D (very important step), then put things
into proper layers ... each one named for the cutting depth. I then save
each layer (deleting all other layers) as a .dxf file, and import it into
Part Wizard. To ensure proper alignment, I'll include a standard sized frame
(typically 48" x 96"), that I use to place the layer. After placement, I
delete the standard sized frame and generate the cut file for that depth.
Once all the layers have been converted to cut files, I save the entire cut
file and send it over the network to the shopbot PC (not included ... you
supply that). I ALWAYS verify the shopbot files with the preview function of
the shopbot control software (to make sure I don't cut through any bolts or
screws I'm using to hold the material to the work surface).
This sounds complicated but it isn't. I recently had a waterbed leak (it was
one of those Somma mattresses with the seven individual tubes ... but I
digress). The deck below the mattress was MDF, and it did it's oatmeal
impression, so they had to be replaced.
From the time I started drawing the parts in CAD (there were six panels ...
2 of one type, 4 of another), until I had the finished parts (made from 3/8"
AC plywood) installed in the bed was around 30 minutes ... including the
cutting time. I don't think I could have set up the plywood in my shop and
cut it with the circular saw in that time. Plus, the fit was ... perfect.
So, for small runs or large, the shopbot is a pretty good choice. The
learning curve is steep, but not impossible.
Economics ... (well, my boss) bought the shopbot because we priced out raw
material (1" x 48" x 96" HDPE sheets), factored in our time and the cost of
the shopbot and dust collection system, and still saved money over having
someone else fabricate our parts and ship them to us. Thus, the 'bot paid
for itself before we finished the first job we did.
Limitations: With the Porter Cable router as the spindle, you're cutting
speed is limited by the the thickness of the material you are milling ...
I'm running between 1.5 and 2 inches per second (90 to 120 inches per
minute). I try to cut no deeper than 90% of the cutter diameter. If you
exceed this, you WILL drag the shopbot off course ... ruining the cut.
Some things are done better with other tools. For instance ... rip cuts are
much faster on a table saw, and you lose less material to the bit. To do
fence pickets, you would do all the straight cuts with other tools, and make
a fixture to cut the tops with the 'bot (bolt the fixture to the work table,
insert a picket, clamp it down, let the 'bot do the cutting, remove and
Hole drilling is usually better with a hand drill ... until you get to
several hundred holes that need to be accurately made! The shopbot is great
for drilling, and does so quickly. We've even done countersinks by starting
with the countersink diameter, cutting down to the depth required, then
drilling the thru hole in a second layer.
One thing to consider is to have Shopbot give you names of people in your
area that have purchased a shopbot. You may wish to sub the work out to them
... avoiding the expense and learning curve issues.
You mentioned putting this in a machine shop. Shopbot also has a plasma
cutter version ... they have some examples of their work done in 3/8" plate
in their showroom in Durham, NC. Yes, I'm close enough that I not only
visited their facility to look over the shopbot, but picked mine up in the
Recommendations. Get the optional table ... don't waste time trying to build
your own. Theirs is well worth the time and money saved (unless you have
lots of scrap c-channel, angle, and hardware, and the time).
I'd recommend the Porter Cable router, but get the rebuild kit just in case.
If you really need to increase speed and reduce spindle noise, the Colombo 5
HP spindle is the way to go. This will require 230 or 460 three-phase power
... you MIGHT be able to run it on 240 single phase but you'll need to
verify this with Colombo. This is an expensive upgrade, but it is a bit
quieter and the power helps you make smoother cuts.
You need a dust collection system. I have a Delta with a cloth upper and the
plastic lower collection bag, and have a trashcan cyclone in front of it. If
the plastic bag starts to fill, it's time to empty the trash can.
Router Bits are very important. I have been using Onsrud bits ... mostly
because they have a great technical support staff that will help you
identify the correct bit (if the web site doesn't help that is). Generic
woodcutting bits may be ok for the material you are working with, but you
will want to check with Onsrud.
Hold down. You HAVE to secure the material to the work table. We drilled 7
holes along each x-axis edge to hold our HDPE sheets. We place the sheets on
the work table, then drill the clearance holes from underneath. We then use
1/4-20 carriage bolts and wing nuts to firmly secure the material to the
table. If you are working with dimensional lumber, you may be able to make
fixtures that hold the material in place. Remember that the carbide router
bits will try (and generally succeed) to cut any hardware in its path
...dulling the bit in the process.
I hope this has answered your questions ... feel free to ask if you have
more questions. I kept this off the group to cut down on the noise.
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