2 sided misaligned and I cant figure it out?

[BigMoose]

Hey guys, I just wanted to throw this out there and see what I am missing. I am doing a 2 sided project for a buddy who needed some iPhone mock ups for a project of his. So I did the model and put it in vcarve. When I ran the first one I got a misalignment on the X axis I checked everything I could think of but it is still messed up. I had it set to flip on the X so I changed it to flip on the Y and recalculated all my tool paths but all that did was move the issue to the Y. I am referencing off the lower left corner. Everything is perfect in the preview in vcarve so I have a feeling I am doing something wrong with the flipping or the reference point. Any tips from anyone with experience with two sided projects would be much appreciated. Thank you. 
 

[red]

I think that it would help if you used pins as a line up tool rather than the setup you are using. Try watching
It is a video on what you need.

[BigMoose]

Jan 25, 2018 20:32:32 GMT -5 red said:

I think that it would help if you used pins as a line up tool rather than the setup you are using. Try watching
It is a video on what you need.

I dont see how pins would be any different. Both the pins and mine provide a point of reference and it dose not change. That is what matters. When I flip the piece it goes into the exact same location it was when the first side was cut. 

[red]

It might be possible that you are not getting it centered properly when creating the files in your computer program. I use V Carve Pro and I went through similar problems when I first started. I found that creating holes helped me center my programs and had less problems at the mill.

[red]

I used to have a setup similar to yours starting in the left corner as my orgin. I now use the center of the spoil board as the center and use the center of my material at that point to do most all my work.

[BigMoose]

Jan 25, 2018 20:50:33 GMT -5 red said:

It might be possible that you are not getting it centered properly when creating the files in your computer program. I use V Carve Pro and I went through similar problems when I first started. I found that creating holes helped me center my programs and had less problems at the mill.

I did my research and I found countless people using this same setup with no issue. If it is an issue with alignment in the software then Vectric need to fix their centering function. Because why have a center if it dont center stuff. 

[BigMoose]

Jan 25, 2018 20:54:41 GMT -5 red said:

I used to have a setup similar to yours starting in the left corner as my orgin. I now use the center of the spoil board as the center and use the center of my material at that point to do most all my work.

My next try was going to use the center of the material. 

[cfunderburgh]

Jan 25, 2018 21:04:33 GMT -5 BigMoose said:

Jan 25, 2018 20:54:41 GMT -5 red said:

I used to have a setup similar to yours starting in the left corner as my orgin. I now use the center of the spoil board as the center and use the center of my material at that point to do most all my work.

My next try was going to use the center of the material. 

I've done this similar set-up. I always work from the center when flipping anything.

[gerry]

You are using xy=0 as your project org, but the alignment point for your block is your upper left. Using that method, you have to then make sure that your board is PERFECTLY CUT. Way too tedious to do and get right. That is why everyone usually centers on the x or y central point. Your board must be flipped EXACTLY over center. DO NOT re-zero your X and Y, only the Z. I doubt very much that it is Vectric that has the problem with centering.    Try the project flip as they suggest (with dowels), then modify the method after you get that correct.

[Deleted]

In Vectric 9 software they have new features to make it easier to do double-sided machining. That being said, I've done a lot of double-sided machining in previous versions and it really only means the user has to think through the process, the results are the same. There is nothing inherently wrong with your setup, machinists essentially do the same, that is clamp against the fixed jaw vice and an edge stop. But they will typically touch off against the workpiece which you are likely not doing. So you'd have to make sure your design keeps the clamping and the top and bottom coordinate systems aligned. The easy way to do this is with dowel pins but if you were to touch off your two vice edges you could achieve the same result.

I use 5/8" long precision ground 1/8" or 1/4" dowel pins pressed into a 0.340" deep hole that is undersized by 0.001" or 0.124" and 0.249" respectively. The pins go in and out with a nice tight fit. I'll use two or three dowel pins for locating the piece, the holes don't have to be symmetric but you have to think through the location relative to your workpiece so an L (and a reverse L) or central location makes it easy. I put the dowel pins on a separate layer of the design and import a toolpath template to generate the Gcode. For the 1/8" pins I use a 0.93" bit and for the 1/4" a 0.125" bit. If there won't be a lot of side load during machining I'll use the following sequence:

1) Clamp the workpiece wherever you want on the spoil board making sure the pins will be in good locations. Machine one sides features and the dowel pin holes.
2) Remove the workpiece and machine the dowel pin holes in the spoil board then press in the pins and clamp the workpiece down on them.
3) Machine the second side features and use a putty knife to pry the part off the pins slowly so it remains parallel to the spoil board. You can remove the pins by prying them straight up so you don't enlarge the holes.

You can also use dowel pins to locate your fences if they have holes in them or register the sides of your workpiece. You can get a box of 100 dowel pins for about $10.

Attachments:

Dowel Pin 125.ToolpathTemplate (6.19 KB)

Dowel Pin 250.ToolpathTemplate (6.16 KB)

[BigMoose]

Problem solved!!! I used the center of the work piece and all is good. Now looking back using the lower left and my jig holding the upper left was kinda stupid. So like others said any variation in material size screwed things up. Thank you everyone for the tips. I am not fond of using dowels for alignment for one off stuff. If it is something I am making a lot I dont have an issue. Just dont want my spoil board being swiss cheese and having to replace it within a month (Joke). Lol

[Deleted]

Jan 26, 2018 14:41:05 GMT -5 BigMoose said:

Problem solved!!! I used the center of the work piece and all is good. Now looking back using the lower left and my jig holding the upper left was kinda stupid. So like others said any variation in material size screwed things up. Thank you everyone for the tips. I am not fond of using dowels for alignment for one off stuff. If it is something I am making a lot I dont have an issue. Just dont want my spoil board being swiss cheese and having to replace it within a month (Joke). LolI 

I machine a 2" grid of holes on my spoilboard so I can use them in any design without having to make additional holes. I also design fixtures to fit them so that I get repeatable mounting.

[gerry]

Jan 26, 2018 14:41:05 GMT -5 BigMoose said:

Problem solved!!! I used the center of the work piece and all is good. Now looking back using the lower left and my jig holding the upper left was kinda stupid. So like others said any variation in material size screwed things up. Thank you everyone for the tips. I am not fond of using dowels for alignment for one off stuff. If it is something I am making a lot I dont have an issue. Just dont want my spoil board being swiss cheese and having to replace it within a month (Joke). Lol

I use the same setup you have to machine both double-sided and regular stuff. For most of my regular stuff, I machine on the spoilboard and reference the spoilboard for Z. That assures that I don't cut into the spoilboard. When I want to place dowels or screw down my workpiece, I have a reserved piece of 20"x20" MDF. I planed the MDF to assure flatness and always re-orient to in the same direction as when I originally planed it. I hold the MDF down with the same setup as you have now. It takes less that a minute to swap it in. I drill the holes in the MDF for double-sided, use 1-1/4" screws for holding down the stock (3/4" Stock on 3/4" MDF). I can now cut into the spoilboard if I want or run double-sided. MDF is cheap.

P.S. I plug up the dowel holes after the run. Too many dowel holes and it got confusing when it came time to flip the piece.   Also, I keep a small Chisel Plane on hand to clean up the screw holes in the MDF. They pull up the MDF slightly into a bump, and it can throw off a delicate Vcarve. If you're careful, a plain chisel will do. The Chisel Plane is fast and easy (one of my favorite planes).

[aluomala]

Jan 27, 2018 22:49:44 GMT -5 gerry said:

Jan 26, 2018 14:41:05 GMT -5 BigMoose said:

Problem solved!!! I used the center of the work piece and all is good. Now looking back using the lower left and my jig holding the upper left was kinda stupid. So like others said any variation in material size screwed things up. Thank you everyone for the tips. I am not fond of using dowels for alignment for one off stuff. If it is something I am making a lot I dont have an issue. Just dont want my spoil board being swiss cheese and having to replace it within a month (Joke). Lol

I use the same setup you have to machine both double-sided and regular stuff. For most of my regular stuff, I machine on the spoilboard and reference the spoilboard for Z. That assures that I don't cut into the spoilboard. When I want to place dowels or screw down my workpiece, I have a reserved piece of 20"x20" MDF. I planed the MDF to assure flatness and always re-orient to in the same direction as when I originally planed it. I hold the MDF down with the same setup as you have now. It takes less that a minute to swap it in. I drill the holes in the MDF for double-sided, use 1-1/4" screws for holding down the stock (3/4" Stock on 3/4" MDF). I can now cut into the spoilboard if I want or run double-sided. MDF is cheap.

P.S. I plug up the dowel holes after the run. Too many dowel holes and it got confusing when it came time to flip the piece.   Also, I keep a small Chisel Plane on hand to clean up the screw holes in the MDF. They pull up the MDF slightly into a bump, and it can throw off a delicate Vcarve. If you're careful, a plain chisel will do. The Chisel Plane is fast and easy (one of my favorite planes).



I think this is the solution (short term, anyway) that I might go with. I was thinking of putting holes in my stock spoilboard (as Fean described it, on a 2" grid spacing), but I kind of want to keep that perfectly flat/pristine. I had some fairly complex system designed in my head (holes every 1" on the centerlines of x- and y-axes), but I figure if I set up a few pieces of MDF as you describe it:

1) MDF is cheap, and easy to surface (I have a 2" Amana flycutter with the replaceable blades (I have both MDF and general purpose blades)) ;

2) if you make a mistake in your design, you have only screwed up one small piece of MDF board, and not the spoilboard pieces and ;

3) maybe most importantly, you can have a bunch of these boards and when one project is cutting, you can prepare other pieces on these boards, and simply swap them out, minimizing prep time. I had a basic system along these lines (scrap MDF that is longer than my project pieces that I used an airgun to tack to the MDF (way faster than screwing) and used clamps at either end to hold it down onto my PirahnaFX machine. Works a treat, but I think there is a better way (as I outlined above).

I am going to try to come up with some different designs (still waiting on my machine to arrive: ordered it in early Dec from a distributor in Quebec (Axiom doesn't ship directly to customers in Canada) and have been waiting impatiently ever since)), but I think each board may have to be different (depending on project size, etc), so will stick with simplicity until I learn from trial and error.