I need an expert! i am struggling with finishes on HDPE and MAPLE!!settings or motor?

[RoyalRacksUSA]

The gears are cheap. If the gear racks are dry, you need them. Looking at your parts - you need them. When you put the new ones on, crank them on until the wrench almost bends. You'll need an 1/8" allen wrench. A large adjustable wrench will help pry it off of the shaft, like a pickle fork, if you don't have a gear puller.

You have a BT Standard machine with a 4G drive system. This uses Gecko motor drivers. This is an open loop system, meaning that if you push it too hard, it will lose steps, and position. The other model available - geared more towards production work is the Alpha model. It has encoders on the motors that self-correct if it gets out of step. It is not a 'true' closed loop system, but it has more power than the 4G (about double that of the Standard) and more power/torque on a CNC router means smoother cutting.

Your Standard is fine for what you are doing, but looking at your cuts, it needs to be tuned up. Also, the router is OK, but consider upgrading to a spindle (it doesn't bog down like the PC router) after you make some money.

-B

Thanks again. I applied grease to everything and the pinons and rack seem to be meshing well. Still trying to understand why the new gears if they are not worn and meshing correctly?

What is more important, a spindle or getting an alpha machine all together?

What do you mean the gears look dry? Are you referring to just grease? I can't find much play when the motors are powered up, MAYBE. .004. After maybe replacing gears, what else can I do? What cutters would you suggest for a good finish on either material? Feeds and speeds?

Seriously, thank you for taking some time to help me. I was also told to get nice collets from precise its.com. So those are on the way

[Brady Watson]

Pinions are cheap...less than $50 for the pair. They are the only consumable on the machine besides the spoilboard. If they were run dry for even a week or two, they are shot. When they are worn they will kill your edge quality.

Hold down is a major factor in edge quality. Just screwing down a sheet in a few places is not good enough if your intent is to get top quality parts. Hold down is about 85% of the entire work involved in machining anything. Just onion skinning the parts (film left on bottom) does NOT mean that the parts cannot be pulled into the bit.

The toolpath strategy, if quality is the concern, should be made to cut the part 90% of the way with a .02" allowance, stepping down say, .1 to .2" per pass. Then come back and do a final pass cleanup @ 100% depth, stepping down the whole way with 0 allowance to shave off that .02" - nice and steady at a speed proportional to the size of the part. You are not going to get clean parts that are 3" in diameter cutting at 3 inches per second...this violates the laws of physics.

The rest of the machine should be checked with a dial indicator for slop. This is the only way to gauge what is up. The v-roller bearings can be adjusted as needed if there is slop between them and the corresponding rail.

Climb vs conventional - if the scrap is cleaner than the part - reverse the cutting direction.

Your post processor in CAD/CAM should be outputting arcs & not straight lines when cutting curved parts. Toolpath and save a simple profile toolpath around a circle. Open up the SBP. It should show about 10-20 lines of mostly CG commands. If it has hundreds of lines of code just to cut out a simple circle - you want to choose a post that commands the tool to cut with arcs - not thousands of very small straight lines to cut a circle.

There are a lot of little things that can be done to chase down quality. This is hard to do on a forum...You can have a tech come to your shop to help you with all of the things I just mentioned & give you some CNC training. You'll have to call SB about this - I have retired from doing this.

-B

[twelchPTM]

I cut alot of HDPE sheet goods and can honestly say I have never gotten a "perfect" edge. You can get pretty darn close but everything shows. sometimes a quick pass with a heat gun can clean it up a little more to. another though that I didn't see mentioned - we once had a guy trying to cut round frames for something. This particular guy thought he knew better then anybody else and refused to use the Partworks software and instead wanted to make his parts using some other program and then export and import into partworks to compile the toolpath. End result was a circle that looked perfectly round on screen but when cut appeared to made of a thousand flat sides. the program he used drew circles with a **** ton of nodes as apposed to the 4 nodes per circle found in partworks. (Brady met the pint sized hipster of which I speak!). Not surewhat softare your using but I figured I would throw it out there.

[ccwerks]

Not sure if this applies, I have seen folks wave a butane torch over HDPE and it smooths everything out