Profile cuts on MDF

I am having a lot of trouble with my profile cuts. I make signs for my wife’s etsy shop, and I am by no means an expert when it comes to vcarve/ easel/ xcarve. I am looking for help. The signs I am making are from 1/4 mdf. They are profiled cuts made for custom name designs. I am spending a lot of time sanding down the cuts after they a)re cnced. I have done several signs where no sanding on the side is required. (smooth finished sides). my machine is now leaving these path marks that I have to sand down. I have tried several different ways of correcting this and I am now stuck. I have attached a picture of the problem. Please help!

It looks like flex it your z check your wheels. Also grab your spindle and check for flex.

Thanks for your response DavidAnnetta,
I will check it out tomorrow. What does it look like, or how would I know if the spindle is “flexing”? Just any movement?

Depending on your issue you may be able to “cheat” it by doing the carve twice.
First make it run like you do now, but fudge with bit diameter in order to actually carve it slightly oversized.
Then make a second run, in full depth, to make it true in size. This will act as a finishing pass.

If the carve was good before but now show these “steps” I would check the mechanical side of things as David mention.

Is the MDF properly dry btw?
Also, what controller/motor system are you using?
Are all belt pulleys tight and Loktited?

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Check your bit for sharpness.

One of the things I learned is the default cut settings are a bit reserved. What spindle/speed are you using, what depth of cut, and rate of feed, and bit size? MDF cuts easily (compaired to hardwood). Are you making dust more than ‘chips’ while you are cutting?

The spindle shouldn’t move easily. If you push hard it should only move a little bit. The step lines show that the spindle is moving (sideways). If your settings are too aggressive for a hobby machine it’s gonna flex ie cut too deep, move too fast, or chip buildup.so what are you cut settings and bit type?

Yeah that looks like some kind of flex or deflection. Probably mechanical.
Normal check list, look for a loose pulley or wheel.
Also flip your belts and look for a squished tooth.
Do you have an upgraded gantry?

FYI: for 1/4" MDF I got this 1/8" down cut bit on a 1/4 shank that I love to use.

I know for sure your bit is dull.

I would hate to have to do it twice! It already takes so long to carve out! My controller is that easel? I use vcarve then easel. It connects to the unit that came with the xcarve I forget what they call it
The pullers are tight, and no I did not loctite them.

I switched out the bits a few times already

Sorry, I am replying on my phone while I am driving home. I will update this with settings and bit type when I get home

correct, I was responding to him asking me if I am getting chips or dust.

I think the stiffness of my spindle if going to be my problem. how can I strengthen the spindle mount?

I am cutting a with :
1/8 fishtail 2 flute.
70ipm
speed setting 1-1.5 on my dewalt router
.045 pass depth

I have tried both the “conventional” and “climb” direction of cut.

I just ordered the bit you recommended, I do not have an upgraded Gantry. I purchased the Xcarve about 6 months ago stock. It had been tough getting it going and I just realized you guys are super helpful and active on here! I have been able to carve out a good amount of signs with success though, I just think the machine now needs some tune up and love.

I have also had a hell of a time trying to figure out how to zero to the bed so I can configure the path to not carve into the waste board. My waste board is a true waste board with tons of cut marks. I don’t mind, but I am wondering if this Is not good for the machine?

How are you wheels adjusted. They should be to tight to move with 1 finger but still can move with 2. Wheels on x and z, you should see where it’s loose when you grap your spindle. This is one of the weak point on the xcarve, this is why so many have upgraded to a linear Z.

Ok, So the wheels on Y should be tight to where I cannot slide the gantry on the rails with one finger, but I am able to with two? Do you have any information on the linear z? I would like into upgrading it.

Wheels should be tight that you cant rotate with 1 finger but you can with 2.

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Running the carve twice do not equal 2x carve time.
The strategy is well versed in the commercial world, you run the bulk of the material removal process with one set of cut parameters (rough carve where infinite precision isn’t required) then a 2nd stage doing the finishing cut of the surfaces.
With optimum use of your machines capabilities you may actually see a overall reduced carve time.

Wow, I definitely needa try that. What does the tool path for that look like? How would I set up that last pass?

@ChristopherHuynh

Hows it going man

yeah so a few problems here it looks like

I would defiantly take a look at your tooling the one suggested and look like you bought it should do the job just fine that is a okay tool

after that tool look into Amana Tools (www.toolstoday.com) spectra coated cnc bits it will last longer

but for sure use a downcut tool on mdf and when you have thicker mdf use a compression spiral tool this will give the best results

I have run the Whiteside tool and the Amana tool at 132 ipm at full 1/4" depth on my big machine with no problems so dont be afraid to push the tool on your x-carve a little

I would suggest 100 ipm 18000rpm .0625 depth of cut on your x-carve (but I have run at full depth on my x-carve with no problems) I would also make sure that you are ramping into the material at the same feedrate as you are cutting

also make sure that your machine table surface is clean and flat and you material is clamped down well

you will be surprised I do not use tabs with mdf as the dust produced will hold the part firmly in most case

and dont ever ever ever use HSS tools with mdf only high quality solid carbide tooling

if you have a high quality tool mdf cuts like butter so do not be afraid to push the tool harder and faster

as far as the dust yes its dust and be sure to wear a mask and use a dust shroud on your x-carve to reduce dust when cutting a good dust shoe with leave the material completely free of dust when its done

hope that helps