ok so ive been trying to get my machine square as it has an issue where one side carves deeper than the other. i thought maybe it was just not square so i took the whole machine apart and added 2 additional extrusions under the wasteboard and reassembled everything making sure everything was completely square
my x axis still has an issue where if i measure from the makerslide to the waste board on one end and then the other the measurements are not the same. and then add to that that those measurements are not the same at different spots on the board
so i think the thing to do is just machine the waste board flat
i plan on using a 3/4" straight bit to skim the board at about 0.001" in a 31" square (about the usable surface of the machine)
ill do this however many times as needed to get the whole surface flat.
my question is, does this sound like the right way to do it?
I am running vcarve pro and did just what you are planning using a 1/2" router bit with a 1/4" shank.
while I thought the wasteboard was flat enough, the MDF had swelled slightly around the edges since the time it was manufactured from the edges to the center was as much as 1/32" difference. I would suggest you set your Z-0 at the center of the board and then run your flattening code.
I was quite surprised to see just how far mine was off.
i have a copy of aspire i was going to use to do it because i like the way you can chose how it routes pockets. i was going to start at lower left but the center may be a better choice. did you create a square to run the cut?
I set it up for 798 mm x 798 mm
When I say I set my Z in the center of the board I then set my x/y on the front left corner and ran it from there. I guess it dosnt matter which way you do it as long as the toolpaths do a slight overlap for complete coverage of the work surface.
oh ok i got you. i misunderstood, thanks!
When flattening your wasteboard do you end up with just the carve-able area flat and recessed from the outer edges? For the most part I think that would work for me, but there are times my work piece needs to extend past the carving area. Do you have ways of working around that issue?
My x-carve is 500x1000 so there is only 12" of live area on the x-axis
That is why I use a piece of MDF cut to the actual work area size on top of the wasteboard. I screwed the top piece down using counter sunk holes and then I was able to cut the entire top surface level. You will lose a little Z axis travel but I have not had any projects yet that needed the extra 3/4 inch.
I am just at this step now… just finished my table 48x50 inches… have the 1000x1000 wasteboard which seems to have come warped up a little on all 4 corners and am now fighting with the idea of having a flat work surface. I was going to use cedar strips that protrude maybe 1/4 inch above the top of the pine frame that can be adjusted strait and level for all 4 sides and then pocket hole my tabletop into that from underneath… but this carving of secondary waste board flat seems like a great way around that… I am a perfectionist so kinda want to start with a perfectly flat table top and a perfectly flat waste board. can you picture what I’m trying to do with those hard wood rails? any other ideas?
you can kinda see that wasteboard warping in the attached picture…
OK… I have an idea on how to get my wasteboard and workspace top perfectly level (or as perfectly level as I can ever get it).
I have a "flat concrete slab in my garage, actually its 4 slabs that make the entire floor (see pic in my post a couple up). there are no cracks or visible imperfections. maybe not level but flat.
what if it flip my table top upside down and put it on this “flat” floor.
Then I flip the wooden table frame upside down and rest it on the upside down table top.
I put 1 - 1/2" spacer under each corner post between frame and tabletop. These corner posts were all cut at the same time and are within 1/16" if not better of each other.
Now I cut 4-6 45" lengths of 2 1/2" hard wood and run them down the inside of the rails of the top of the wooden table frame so the bottom of the strips would rest on the bottom of the tabletop. (remember its upside down)
now just screw these “leveling strips” into the frame.
when I flip the table over the tabletop will be on a fully supported FLAT surface…
Unless I hear of any reasons why this won’t work, I plan on doing it within a couple days as time allows…
I’ll post pics.
Pete
The floor may appear to be flat but if one were to put a straight edge across it on the diagonals I;m pretty sure one would be disappointed with the results.
The xcarve does not really need to be “dead level”. aside from the effects of gravity it could function just fine hanging on the wall.
But the waste board needs to be flat and parralel IN RELATION TO the spindle.
The machine operates from the relation of the tip of the spindle to the wasteboard, ie; home zero or position. When a work piece is placed on the wasteboard, we tell the machine what the thickness of this piece is.
The machine does not really care (if it could) of what is between the wasteboard and the tip of the cutting bit.
If the work piece is .75" thick and we want a depth of cut of .125, the machine is going to position the tip of the bit at .625" above the wasteboard. what ever is in the space above .625 when the spindle comes through is doomed to destruction.
I would suggest zeroing out at the front left corner, then, using the tip of the bit jog down at each corner and the center of the wasteboard. The difference between the highest and lowest points will be how much needs to be shaved off to achieve parralel between the spindle and the wasteboard.
Start at the lowest point and create a file to cut a pocketing path the size of your work area with a depth of what ever the highest point of the surface is and run it to skim the board.
First let me preface by saying I am thinking all this up as I go and have no real experience doing this type of stuff…
I really was just trying to make a work-space as flat as possible (within my means) and very well supported throughout the entire work surface. I’m pretty happy with the way it turned out, seems flat and well supported in the middle. I feel better to have done it this way than to just screw the top into the crooked frame and warped boards…
Maybe I over thought it a little. Maybe I should have started with better wood and made sure it was true.
I flipped workbench top over on relatively flat concrete floor.
cut 4 1/2 inch spacers for all 4 corners
flipped workbench frame over on top of the spacers on top of the table
Added weight to make sure it was sitting flat.
nail gun strips to frame while top is resting on workbench bottom.
screw and pocket hole everything together…
I am planning on carving down a waste board so its perfectly flat in relation to the carver.
I think you did just fine.
As long as the final result is within 1/8" or so of parralel with the x axis gantry, you can mill the wasteboard to perfection with too much trouble.
I need to skim mine periodically due to seasonal changes in humidity but that is only by a few hundredths each time.
Sealing the surface and edges of the wasteboard with shellac helps with the seasonal issue as well.
I do not think anyone really thought of this as I have not seen any mention anywhere I have looked. So I will put my 2 cents worth in.
Using MDF for the main platform is bad. The one that came with my system is warped in several places. To mill it down would require me to find the highest point and run a mill job from there down to the lowest point.
I did think of trying to level it first using washers but found out that its impossible.
The 75mm holes that are put into the thing you use to lock down material are only part of the issue. When you lock down your work piece what happens is that the board will warp in that area due to the force and relative moisture in the air. This board is unacceptable for what we as machinist need for a flat surface. So I am going to take this out and work on getting a new material that not only is water proof but will allow me to use T-Slots for work hold down.
I do not know why they sell this MDF as the platform and it is not perfectly flat.
It is the cheapest way to go but it would be better to have the extruded aluminum like I have seen the smaller units have then put the 1/4 or 1/8 inch MDF on top as a waste board.
So my goal for the next 2 weeks is to get a new platform for my system then I will use the MDF 1/8 in. board on top for cutting. I can mill it down to flatness if its warped.
My guess is it’s all dependant on what level of accuracy an individual is going for.
The mdf waste board is most likely offered based on a balance of accuracy (see previous line) ,
Cost to the company and buyer,
and availability.
For my accuracy needs, milling the board flat was the best option, this may not be tha case for all.
But, one thing is for sure when an ID 10 T operator error occurs, MDF is alot more forgiving than an aluminum bed when the bit goes for the center of the earth.
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I was not referring to just the metal plate only. I would put the MDF on top and resurface it.
Personally I like Phil’s setup and will most likely copy his for mine.
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I had a next wave automation “piranha” and it had the slotted aluminum bed and I did just what you mention with a sacraficial wastboard to protect the aluminum. But in doing so i lost precious Z height.
An aluminum plate on the bottom will give a stable foundaion to build on for sure but MDF will gain and lose moisture with seasonal and even daily humidity changes, and not evenly across the surface resulting in an uneven workspace. This can be mitigated somewhat but not entirely eliminated with a sealer coat of finish, especially on the vertical edges. I find that i have the need to make skimming cut of my board every spring and then again in the fall as the seasons change. I only set it to take off about .003 with the initial pass and then .001 to get any low spots.
I have my machine’s wasteboard fastened directly to the top of my torsion top table. i eliminated the framework under the waste board giving me another 20 mm of Z capacity
That’s not a big deal, though. It’s what I did. Shipping the stock wasteboard seemed too expensive, so I went down to home depot and just bought MDF and had them slice it into some wasteboard-sized pieces.
It’s not fast with a 1/2" cutter, but it doesn’t need to happen very often.
Isn’t flat (to some spec of “flat”) aluminum in a 1m x 1m piece crazy expensive?
I think I will stick to my original plan to get Valchromat and use it in place of the standard MDF.
There are other boards that can be used. I just need it to be as level as I can get it so I don’t break anymore bits on trying to carve plastic.
I have a tube set up for air flow to blow on the plastic but its not enough.
Thanks for the input. 
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I used a series of post-assembly t-nuts inserted into the bottom slots of the lower frame to bolt my entire machine down to a 25mm thick piece of ply. this increased rigidity and removed a lot of variation in my z-axis accuracy.
I used the small amount of play in each corner of the upper gantry mounts to adjust for any further variation. I’m within a half millimetre now which is satisfactory for now.
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As it turns out I just finished flattening my wasteboard (1/2 MDF on top of the stock Inventables wasteboard) the stock wasteboard was high about .07 on the right side in the front and sloped back down some toward the right rear.
I used a 1/2 flat bottomed bit and got very smooth results in terms of the toolpath cuts but oddly, there is now a hump in (about) the middle of the wasteboard of about .30 while all four corners are within .002 of each other. Not sure why. Any and all thoughts welcome.
