Homebrew PCBs

Brian,

The kit will be complete, including structure, motors, drives, wiring 
and software. (The only item in "debate" is whether I'll include a 
drilling spindle or not.) IMO, The tech support issues from offering 
incomplete kits are not worth the hassle and time for a product so 
low-priced.

There is NO difference between the 800 and 500 buck machines because 
they are the same machine! (At this point, anyway. Explanation 
follows.) Here's the issue...

Even the least expensive cnc drill needs certain things. There is 
a "base" cost for these things which cannot be made less. In this 
case, to be called a CNC PCB drill, you need AT LEAST: 

2 motors for XY drive,
2 screws,belts, or other means of moving the axes 
2 drivers for the motors
1 solenoid for actuating the drilling, and a driver for the solenoid.
rails and bearings for the xy and z axes
Support for the pcb
a spindle, or the attachment point for an easily available spindle.
The machine structure to put this all together, including hardware, 
etc.
A power supply
Wiring and connectors
Software
Shipping packaging
A means for customer support and answers to customer questions

Without ALL these things, you don't have a viable CNC drill.

So you play with each category trying to get the best overall value, 
within the 500 buck limit that you guys have set...

And you find that if the machine is made just a bit bigger,stronger, 
faster, then a LOT more can be done than JUST pdb drilling. But as I 
wrote in a post a few days ago, you ALSO find that this "just a bit" 
costs MORE than "just a bit" more... 

Start with this: A 5"x8"x1/2", moving table, XY stepper ,solenoid Z, 
pcb DRILL only--(which means the guide rods/rails can be VERY light, 
just look at what the Roland machines use!) In other words, the 
barest minimum that could properly be called a CNC PCB drilling 
machine. (This is what I had in mind originally for a 500buck cnc 
drill.)

Then, luckily for you guys, feature creep kicked in<G>

Anyway, going from that to an 8"x10"x2", 3 stepper, full 3d capable, 
STURDY 3/4" rails, acme drive, AB nuts(because a pcb drill(only) 
doesn't need AB if the software always approaches the drilling point 
from the same direction), A stiffer structure to accomodate the much 
thicker items likely to be placed on the table to be cut(like 
electronics enclosures, for cutouts/engraving), which requires an 
increased throat that changes the moment loads and calcs
(geometrically)--not necessary if 1/16 pcb material is all you need 
to accomodate, AND all the other related things that make the result 
much MORE than a CNC pcb drill...

In this case it all means a difference in selling price of about 300 
bucks. As I wrote, each "little" upgrade or improvement causes a 
chain reaction to other parts of the design. But for me it's hard to 
use 1/2" rods, when 3/4" will cost the same in volume... And to sell 
a moving table, when I KNOW a fixed table is better for a wider 
variety of things...

Now what I have to decide, is whether I think I can make any profits 
selling an 800 buck machine for 500. And whether simply providing the 
500 buck CNC PCB drill ONLY, is a better choice, business wise. 

Or whether the increased usefullness is worth the 300 bucks to my 
potential customers? 

My current belief is that the bigger, better machine will be more 
useful to more people. So I mentioned that what I'm thinking I will 
do is to initially offer an 800 buck machine for 500. But to pretty 
quickly increase the price to 800, and bring a new machine that is 
pcb drill only to market for 500 bucks.

I have no interest in providing a "partial" solution. So whether 500, 
or 800, or 1000, or 5000; my machines are complete. Just with 
differing capabilities of size speed, and "duty cycle".

Side note: I used to work for a copier company as a Service Tech. We 
had a machine that was rated 5000 copies per month. Of course this 
was based on a 20 day work month, so it was REALLY rated for 250 
copies per day. I had a heck of a time getting this point across to 
my customer who had monthly breakdowns due to running 2-5K month end 
reports... "But they said it was good for 5000 copies per month!" 
(that's what duty cycle means.)

Hope this helps,

Ballendo

P.S. About the only "time consuming" step I "could" pass on is the 
pcb assy. and wiring. Since this group obviously can do that, perhaps 
that's something I'll consider... 
But I have to stress that my experience with low-priced products 
shows that customer support can kill profitability quicker than 
almost anything else... So it all has to balance. Because I'm not 
doing this for grins<G> 


--- In Homebrew_PCBs@yahoogroups.com, Brian Schmalz <brian.s@l...> 
wrote:
> Ballendo,
> 	I'm totally interested in the $500 machine. For me, $800 is 
less
> interesting. What differences would there be between the two 
machines?
> 
> What software would you need to run it? I'm assuming the $500 
includes no
> electronics, correct? I really like the idea of giving it the 
flexibility
> that the user can modify it to do other (simple) things like pnp, 
routing,
> front panel milling, etc.
> 
> Are there time consuming steps in the assembly that you can let the
> user do (more of a kit) to save cost? I'm happy to spend 40 hours 
> putting together a kit if it will cut $100 from the cost. (Just 
> cause it's fun to put together kits!)
> 
> *Brian
>