Notch in the Vector

[rsetina]

I created a pocket for a project and there's a notch in the first pass. This happen previously but I found and fixed a problem with an extra point in the vector that created a z pattern in the vector. Now that it's fixed, I'm still getting a notch in the first pass of the pocket. The notch seems to be gone in the subsequent passes. I check the vectors again and they are good. I'm also having a problem with the cut stopping for a second before continuing along a curved portion of the machining. When the center circle is machined, the machining stops at 12, 9, 6, and 3 o'clock before continuing on also. Never had a problem before until the upgrade. This all started with the upgrade to 10.XXX that has the thread cutting tool. I attached the file if anyone wants too look and see if I missed something.

Five Compartment Tenkara Box Round Center.crv3d

(339.5 KiB) Downloaded 80 times

[gkas]

The machining looks fine. Are you using a new Post Processor?

[rsetina]

I’m using the same PP as before for the Shark HD 2.0. That was one of the things I checked. I noticed the notch is the starting point for the cut. The green point on the vector. Would that be a reason for it? I’ll try to upload a photo. I’m using my iPhone at the moment.

[TReischl]

Looks like mechanical deflection on the machine to me.

[rsetina]

Looks like mechanical deflection on the machine to me.

What do you mean by a mechanical deflection? I’m thinking it mean that there’s a problem with the threaded rods or gears? It’s happening to all of the pockets in different direction so how would that relate to the deflection?

[Adrian]

Try adding a ramp to the toolpath which will reduce the load on the bit as it does the first plunge. That won't cure the issue but will confirm that it is a mechanical issue which it certainly looks like. Whenever the gear cogs on my machine need replacing the cuts look like that (not so severe).

[rsetina]

I’ll give that a try. Thank you.

[TReischl]

Looks like mechanical deflection on the machine to me.

What do you mean by a mechanical deflection? I’m thinking it mean that there’s a problem with the threaded rods or gears? It’s happening to all of the pockets in different direction so how would that relate to the deflection?

Exactly what I said, a mechanical deflection. Not dissing your machine but the Sharks are not known for their rigidity. Don't take offense. Any CNC machine is better than no cnc machine at all. It is just a matter of determining what a particular machine can handle. My first one was home built. Max feed rate was 60 IPM on a good day. Learned a lot of lesson on that first one, my second one has cut at 800 IPM and regularly runs at 300.

Probably NOT in the threaded rods, not sure where there are gears in that machine :::shrug::::. Grab the collet and see if you can move it side to side.

Sort of brings up an interesting point. Virtually all the machines we see these days are moving gantry style. A moving bed machine avoids all the issues of spindles deflecting. Problem is they take up tons of floor space. I notice that a lot of the chinese type machines are using a hybrid design, gantry stationary but X moves along it while Y is a moving table.

[mtylerfl]

My ShopBot Buddy moves the table in X. The stationary gantry allows the spindle to go along Y

[rsetina]

Looks like mechanical deflection on the machine to me.

What do you mean by a mechanical deflection? I’m thinking it mean that there’s a problem with the threaded rods or gears? It’s happening to all of the pockets in different direction so how would that relate to the deflection?

Exactly what I said, a mechanical deflection. Not dissing your machine but the Sharks are not known for their rigidity. Don't take offense. Any CNC machine is better than no cnc machine at all. It is just a matter of determining what a particular machine can handle. My first one was home built. Max feed rate was 60 IPM on a good day. Learned a lot of lesson on that first one, my second one has cut at 800 IPM and regularly runs at 300.

Probably NOT in the threaded rods, not sure where there are gears in that machine :::shrug::::. Grab the collet and see if you can move it side to side.

Sort of brings up an interesting point. Virtually all the machines we see these days are moving gantry style. A moving bed machine avoids all the issues of spindles deflecting. Problem is they take up tons of floor space. I notice that a lot of the chinese type machines are using a hybrid design, gantry stationary but X moves along it while Y is a moving table.

No offense taken. I appreciate your input and I know the Shark isn't the sturdiest machine out there. If I had to do it again I'd buy something different. I re drew the vectors and that seemed to solve the problem. I think with drawing rectangles and circles and cutting them, welding points and all, I must have missed a small deviated vector here and there. Thank you all for you help. I must appreciate all the input.