[bwiab]

Hey there... Went to surface my spoilboard and noticed that the ridges of the cut will require some tramming adjustment. But what has me concerned is that the surfacing bit cut the first past completely across the board and then began to miss the middle of the board. Table is darn near perfectly level. Any ideas on what can cause this? I'm using a whiteside 6220 2" surfacing bit. I think my settings are probably too high and I mistakenly set my pass depth to the cutting depth, but not sure that should effect the surfacing the way I'm describing.

Here's the table with about 10 passes before I stopped the machine.

Attachment 475616

Here's the settings for the bit that I used.

Attachment 475618

I'll probably dial down the spindle speed. Not sure that will do anything though. Any insight appreciated.

[bwiab]

Doh... had it set to climb.... probably the source of my mistake... what do you think?

[mactec54]

Doh... had it set to climb.... probably the source of my mistake... what do you think?

That would not make any difference to the cut, put an indicator in the spindle and move it around the table and see how much it is out, it could be the Gantry or even the base frame, the extrusions are not flat or straight, using a carpenter's level is not going to be very accurate, for a machine table, it also could be the sheet that has different thickness across the sheet, so see if you can do some accurate measurements of the different parts of the machine

[bwiab]

Thanks. I will check it out but have been running into other problems with my machine today... :drowning:

[routalot]

Is there any support beneath the spoilboard?I ask because I'm not familiar with the machine and I wonder whether releasing the stresses from the manufacturing process on one face will have permitted the board to cup.You could lay a straight edge in the region to see if it is actually flat.

While it might not have any bearing on the spoilboard,you are running that large tool rather faster than I would.I wouldn't choose to go much faster than 8500 rpm with a 2 inch diameter.

[bwiab]

Well... I messed around with the tramming and got a 16" x 16" area pretty flat in both directions... then I went to surface the whole board. The area to the right of the red line is flat. The area to the left of the line has ridges... I ran my surfacing tool path primarily in the x axis (perpendicular to the red line) see pics below. Any ideas... I dropped the speed down on the spindle to 11000 rpms and 150 IPM... maybe still too fast?

Machine is definitely out of level. Ran first pass at .06" and it cut the whole sheet. I have an aluminum frame and the sheet was held down by vacuum. flipped it over and glued the top sheet down to the plenum board. I surfaced that at .03" and I had a low spot as designated by the red semicircle. Not worried about that as much as I'm worried about the ridges... any thoughts...

Attachment 476644

Attachment 476646

[routalot]

I'd be checking for play on the side with the semicircle.If the machine has seen a lot of use there might be some play at some point in the structure.It could be as simple as a nut backing off a touch from vibration.Absolute level is nice to have,but less important than having the rails precisely in the same plane-even if it is a touch out of level.If this can be shown to be the case,then redo the tramming with a piece of plate glass on the table to bridge the unevenness.

[ger21]

If it's missing spots, either the rails are not coplaner, or the table has dips or high spots. If you surface one side, and there's a high spot, it'll be a low spot when you flip it.

[mactec54]

Well... I messed around with the tramming and got a 16" x 16" area pretty flat in both directions... then I went to surface the whole board. The area to the right of the red line is flat. The area to the left of the line has ridges... I ran my surfacing tool path primarily in the x axis (perpendicular to the red line) see pics below. Any ideas... I dropped the speed down on the spindle to 11000 rpms and 150 IPM... maybe still too fast?

Machine is definitely out of level. Ran first pass at .06" and it cut the whole sheet. I have an aluminum frame and the sheet was held down by vacuum. flipped it over and glued the top sheet down to the plenum board. I surfaced that at .03" and I had a low spot as designated by the red semicircle. Not worried about that as much as I'm worried about the ridges... any thoughts...

Attachment 476644

Attachment 476646

The problem with tramming off the table is the table was not a flat true surface, what you need is a machined lapped flat surface this can be a granite plate that is parallel to the 2 faces, it can be a steel plate but must have to 2 faces parallel

So now you have a table that is not true, and the Tram is still out. so, you will need a plate to sit on top of the table and then tram the spindle off the plate, check it at the sides and in the center of the table

You need to Tram in all 4 positions 0° / 180° and 90° / 270°

Before you start level the machine as best you can, this is important, as this will affect the Tram, so if you move the machine you will have to level it the same each time or the tram will be out.

You could check the rails also to see if they are parallel to the top of the aluminum extrusion, then level the machine and Tram the spindle

[tuanifab]

My setup had about 1mm of difference from left to right, across the x-axis. It was basically planar, but a dip like you have isn't really a surprise based on manufacturing imperfections in both the extrusions and the sheet MDF combined.

I made a base plate of 3/4" Baltic Birch, faced it, then added T-track with MDF in-between. Now I'm working on recessing in the T-Track a bit so I have more depth of the MDF top surface to work through.