[carter j]

hi.

when using a 90 degree vbit it seems to just rip through the material or create a fan shape thats partially cut into the edge.
ive tried different materials, different feed rates and depths, but it all produces a similar bad finish. except mdf, it works mostly fine on that.
i increased the spindle to 20 000 rpm but i think i may have a problem with it. it doesnt seem to have a lot of power.
for 2.2kw chinese spindle i would have thought it would easily carve through any soft wood. ( ive had it stall a couple of times with shallow cuts using a 5mm end mill. but hey, im new to this.)

some of the wood ive been using was a little below average soft pine at first but it seems to do it on nearly everything i try to v carve.


the vbit was new, but it was cheap. so am wondering if its just that or could there be other reasons for it?

i attached some pictures of the results im getting. any help would be muchly appreciated.

thanks

[ger21]

Looks like the spindle may be spinning much slower than you think, which may explain the stalling. It shouldn't be slowing down at all, let alone stalling.

Next time show some unpainted pics. Is that plywood?

Get the spindle sorted out first, then make sure you have a good quality, sharp tool. Generally, the harder the wood, the better the results will be.

[carter j]

thanks,

yes it is ply wood. i couldnt find any that i hadnt painted sorry
i didnt want to buy expensive tools to begin with til i knew what i was doing. just trying to limit the financial damage when i inevitably destroy stuff. but i will.

i wouldnt be surprised if it is speed related. trying to program the damn chinese inverter was/is a nightmare. its a sanyu sy6600 if that means anything to you.
i tried getting help from the seller but they just sent me a manual for an sy8000. it was similar enough but doesnt explain a lot.

if the spindle = 400Hz 8.5A and 220V
should the running frequency, max output freq and upper limit freq all equal 400Hz?

[ger21]

Try looking through some of the threads for the Huanyang VFD's and their settings. It might point you in the right direction.

Cheap plywood + cheap bits = bad cuts.
Pine is also difficult to cut cleanly.

[carter j]

will do,

thank you.

[pippin88]

Make sure it is spinning the correct direction, not in reverse.

[gregoose]

I had a similar problem with cheap bits on plywood. I think it was a harbor freight bit and some home-cheapo plywood. Went back to home depot and dropped $20 on a diablo v bit and it cut smooth as silk with nice clean edges left over. (on the same plywood).

[TTalma]

It looks like the bit is shot, so I would guess it's the cheap quality of the bit, or as others have suggested the bit is going to slow or backwards. If it's going the correct speed it's probably direction. I've found that even the cheapest bits work well for 1 or 2 jobs. So if the first cut is bad it's probably not the bit.

For the stuff I do I've found the eagle america bits are the best $ vs. performance.

[louieatienza]

You don't have to spend a fortune. Unless you think $15-20 is a fortune. A few extra bucks now will save you hours of time and frustration down the road.

For wood, I would try vcarving using climb milling. Works well especially when cutting easy to tear wood like pine...

[Claude Boudreau]

the first example (red ) look like wood that is not dried enough.Also if you are pocketing with the v tool the tool tip does most of the work witch might take a toll on cheap bits.

hi.

when using a 90 degree vbit it seems to just rip through the material or create a fan shape thats partially cut into the edge.
ive tried different materials, different feed rates and depths, but it all produces a similar bad finish. except mdf, it works mostly fine on that.
i increased the spindle to 20 000 rpm but i think i may have a problem with it. it doesnt seem to have a lot of power.
for 2.2kw chinese spindle i would have thought it would easily carve through any soft wood. ( ive had it stall a couple of times with shallow cuts using a 5mm end mill. but hey, im new to this.)

some of the wood ive been using was a little below average soft pine at first but it seems to do it on nearly everything i try to v carve.


the vbit was new, but it was cheap. so am wondering if its just that or could there be other reasons for it?

i attached some pictures of the results im getting. any help would be muchly appreciated.

thanks

[Khalid]

are you using DIY machine? May be flex in your machine...

[Devastator]

Are you trying to do full depth in one pass? Might try a roughing pass followed by a finish pass.

[wizard]

i'm with the guys suggesting to sort out the spindle issues first. That spindle ought to be able to drive a 5mm bit with no problem in a variety of woods assuming a reasonable feed rate. Get the spindle to work correctly with a good end mill and then look at what you are getting quality wise. Oh by the way a spindle running backwards is a possibility and could be an embarrassment but at least you are running the end mill into wood, it doesn't work well at all if you run it into stainless (don't ask).



As for the cutting tool there can be massive differences between off the shelf cutters. It may seem counter intuitive but it can really pay to use good cutters while learning as you want to understand what a good cutter is capable of and understand how the cut quality degrades over time until it is too dull to go on. As for your current V bit It could very well be a bad cutter out of the box. I can remember a few years back getting drill bits in through one of our vendors from an American manufacture that frankly where crap. The grind on them was so bad I couldn't drill mild steel so we had our supplier change to a different manufacture. What a difference! That American manufacture apparently went under which is no surprise to me. The point is, it isn't so much where the bit comes from but rather does the manufacture have decent quality controls in place.

[louieatienza]

Here's the deal on CNC router bits. Most may look very similar to the ones bought at big box stores. And indeed, we use many tools intended for hand held routers on the CNC. The big yet subtle difference is that, with wood bits, CNC tools have usually higher rake angles,more relief, and larger gullies. This allows for chip evacuation. The problem is in a hand held situation this can cause the router to pull into the work creating a very dangerous situation. Bits for handheld use are designed for anti kickback, and chip limited to reduce radial DoC, and reduce potentially the severity of injury should an accident occur. However this impedes chip clearance on a machine that is much stronger and faster than any human.

Just the same, it would be unsafe to run CNC tooling on a hand held router unless table mounted. Many older bits don't have anti kickback features as well.