Step and Servo Motor Sizing Software for CNC

I see a lot of folks wondering what size motors they need for their CNC conversion projects.  Is biggest always best?  How fast will it go?  Lots of questions.

Because of that, I decided to put some of the calculations I routinely use into our G-Wizard CNC Calculator’s latest release (1.641).  The calculation screen looks like this:

Let’s go through each line and see what it’s purpose is and how to use the calculator.

We start with the Peak Torque Calculation.  It’s purpose is to determine what axis speed you’ll have when your motor is operating at peak torque.  I like to make this the rapids speed for a machine so that the peak is matched to the fastest motion.  To calculate the axis speed at peak torque, enter the following:

-  Motor Torque Peak:  Ideally, you’ll get this looking at a power curve from the manufacturer.  If you don’t have one, I suggest trying 2000 rpm for steppers and 3000 rpm for servos.  Most manufacturers can provide you with this information and it is worth having.

-  Motor Drive Pulley Ratio:  If the motor directly drives the leadscrew, enter a value of “1″.  … Read the rest

Ilia’s Electric Chopper Build

I first became aware of this project and the site it is on (Endless-Sphere.com) when traffic started coming to CNCCookbook from there.  I always go check out new traffic sources because it is usually something interesting.  Boy did that turn out to be true!

I was getting traffic because Ilia had kindly responded when asked about good sources of information to learn CNC and machining with a link to CNCCookbook.  Better still was his project–an Electric Chopper Build.  I love it when someone starts a totally over the top build.  It really captures the imagination and reaffirms what I love to tell people:  Once you have a machine shop in your garage, you can build practically anything.

I urge you to go visit Ilia’s Electric Chopper build thread and check out the many pictures there.  Meanwhile, let me tantalize you with these photos:

It’s coming together with wheels on.  Still need the motor/tranny, batteries, and various other odds and ends.   Looks sharp!

Chopper style suspension and forks is a thing of beauty…

The electric motor is housed in a Suzuki 6-speed transmission.  … Read the rest

Facebook IPO Day

The big news throughout a lot of Silicon Valley has been Facebook’s IPO.  It opened on NASDAQ for the first time today and wound up closing for about the same price it started at.  I have a lot of friends who bought a couple shares just to see what it would do.  Myself, I am content to sit on the sidelines and watch from an IPO standpoint, but from a Facebook user standpoint, I like it.  If you like it too, be sure to get involved with CNCCookbook via Facebook.

There is a CNCCookbook Facebook page you can visit, Friend, and all that other Facebook stuff.  I post to the timeline there a note every time I do a new blog post here.  See if you can guess what the logo image (included in this post too) is a Rhino3D model of.

At the bottom of every post is a Facebook icon that lets you talk about the post on your own Facebook page.  We really appreciate your help getting out the word, whether via Facebook, Twitter, Google+, or your own web site.… Read the rest

Cool Idea: Convert a Digital Caliper to a Tool Setter

MuellerNick in Germany has come up with a neat idea.  He has converted a digital caliper into what is essentially a height gage with a round hole in the base so that it can be used on a flat reference like a surface plate or on a reference that protrudes through the base like a tool holder.

Check out this video for more:

If you’re wondering why you’d use a beast like this, check out my 2 part series on tool length offset and ways to manage that tool data.

If I was going to make one of these, the other thing I’d do is make sure the friction clamp feature of the calipers was functional.  It’s useful to keep tool stickout at a consistent repeatable length once you’ve encountered conditions that cause chatter.  If you have the same stickout, same tool type (same model and manufacturer), same tool holder type (same model and mfg), and the same spindle, chatter conditions are reproducible.  This means that once you know where they occur, they can be avoided if you keep all those variables constant.  … Read the rest

The Top 25 Pages People Come to CNCCookbook to Read

CNCCookbook as a web site sees a lot of traffic–over 100,000 visitors a month.  We bill ourselves as offering “Software and Information for Machinists,” but what are the top pages that bring people to CNCCookbook?

Here they are by category:

Software

It’s fitting that our #1 category is software.  Here are the pages in order of popularity:

G-Wizard Calculator:  Our wonderful tool for helping machinists to calculator everything from Feeds and Speeds to Thermal Expansion to Unit Conversions, Trigonometry, Thread Specifications and more.  We’ve got some deals available if you check out our deals page.

G-Wizard Editor:  Our g-code simulator, editor and backplotter.  It’s free while in Beta test.

CNC Software:  This is an article that rounds up all the different kinds of Digital Tooling available for CNC machinists and explains what problems each kind of software solves.

Gearotic Gear Design Software:  Art Fenerty, father of Mach3′s, very special CAD/CAM for designing and simulating gears as well as creating g-code to machine them.

CNC Simulators, Backplotters, and Viewers:  An in-depth look at what these tools can do for you.… Read the rest

15% Off Sale on G-Wizard Calculator!

We’re on a campaign to double our user base in 2012 versus what it was in 2011.  Every so often, we goose our sales by offering just a few 15% off coupons good on our 3 year subscription.  It doesn’t happen every month, and we only offer enough of the coupons to hit our sales goal–it’s first come, first served.

To use the coupon code, just order the 3 year subscription from our purchase page and enter the “15OFF” code where it asks for a coupon.  But do it now, before the coupons run out.… Read the rest

When to Use a Spot Drill

Machinists are familiar with spot drills–they’re stub length and have little or no flutes.  These little drills are designed to be extremely rigid so that they can precisely spot a hole for a twist drill.  The goal is use the spot drill to make a little dimple in the workpiece that keeps the twist drill from walking so that the hole winds up in the right place.

Is a spot drill necessary every time an accurate hole is to be drilled?  Not necessarily.

If you use a carbide drill, or a screw machine length drill, spotting is typically not needed.  The carbide itself is so rigid compared to HSS that the drill will go where it is pointed.  As a matter of fact, most manufacturers recommend against spotting either a carbide twist drill or an insertable drill because its easy to chip the carbide in the dimple.  Screw machine length twist drills are much shorter, so they’re less likely to flex as well.  In general, you’ll save a lot of time if you can avoid spot drilling.  Investing in a set of screw machine length twist drills is well worth it.  … Read the rest

EDM’ing a Sweet Tool Height Setter

I was trolling through Practical Machinist posts for something interesting and came across this sweet project.  This fellow has used an EDM, a mill, and a lathe to make a really nice tool height setter.  EDM is an acronym for “Electrical Discharge Machine”.  It literally uses electrical sparks to disintegrate the metal.  There are electrode EMD’s, that plunge a conductive electrode into material, and there are wire EDM’s.  Think of the latter as being a ridiculously fine and precise scroll saw.  EDM is slow, but it has the ability to carve out shapes that would be next to impossible with other methods.  They can also be used to cut extremely hard materials, such as the carbide used in this project.

A Tool Height Setter is used to measure the height of your tools so you can fill in the tool table on the CNC to adjust for that height.  Some use electronic touch sensors, and some use an indicator like this one.

Check out the link.  Here are some sample pix from the article:

First, use a Wire EDM to cut all the parts out.  … Read the rest

Shopmade CNC Press Brake

Press brakes are cool machines for bending sheet metal. The CNC variety have what is called a “back gage”. You insert the sheet metal through the opening until the back of the workpiece hits the “back” gage and step on the pedal to do the bend.

You can set up a variety of tooling in the opening, and a skilled operator can walk the workpiece through each station of tooling to make a finished part:

Meanwhile, there’s a guy over on CNCZone who has done a post showing how he built a CNC press brake from scratch. Very cool project! Here are a couple videos and pix:

Demo of the back gage showing how it can move in 2 axes…

Bending some test parts…

Cylinder raw materials, and finished cylinders (this fellow does this kind of thing for a living, BTW)…

Machining the upper and lower die holders…

Plate was flame cut (2600lbs worth!). Ram is guided by some large two truck linear bearings…

He built a plasma table too and used it to cut the pieces for the hydraulic tank…

Back gage and hydraulic manifolding…… Read the rest

Pssst, are you a cheapskate like me?

Are you a cheapskate like me?  It’s no problem.  Our money doesn’t go as far as it used to and we need all the help we can get.

And, I hate companies that hide their coupons, ration them only to new customers (why not give your loyal customers something too), give rebates that are hard to cash in on, or otherwise rely on you to be your own worst enemy so you won’t get the deal.  It’s hard enough actually being my own worst enemy without having to be reminded of it constantly.

Because of that, I’ve create a special “Cheapskate Page” where you can always find whatever deals we currently have going on.  No more need to search for coupon codes, sales, and the like, they’re all right there on our page.

Go ahead, check it out.  You know you want to.… Read the rest