Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

how would a machinist program this?

how would a machinist program this?

how would a machinist program this?

This might not be the correct thread but I have a part with some curves/radii in it, and I want to make sure I am dimensioning it as easy as possible for the machinist. The way it is currently dimensioned I know that you can figure out the curves if you do all the math, but how would a machinist actually go about and do this? Do they have a program where they can easily drop these radii in and make them all tangent? Or would it be easier if I gave center locations to all of the radii? Also is it easy for a machinist to program a profile for whether the machine should follow the outside or the inside of the radii? I have several parts like this and i want to make sure the drawings make sense. Please see attached.

RE: how would a machinist program this?

Just draw the part accurately and simply and they'll make it work. No two machinists will want the same numbers (radii centers vs radii tangent points vs apparent intersection pts). It also depends on what the controller is, whether it's programmed at a computer on some sort of CAM software, or if it's programmed at the machine using some manual input on the controller.

If you don't know much about machining (and even if you do) you'll do more harm than good by trying to make a funky drawing "made for the machinist" rather than an appropriate design drawing that adequately defines the part and shows the design intent.

The best thing you can do for the machinist is to not over-tolerance your drawing. If a three-place dimension is defined as being +/- .005" then you should really ask yourself if you need that tight of a tolerance on fillet radii.

tl;dr: If there's enough information on the print to /draw/ the part; there's enough information on the print to machine the part. Your desire is great. It's good that you wish to look at your output as if you were the person making the part. That will solve a great many things, but at a certain level 'unintended consequences' arise.


All that said, the only exception is if you're making actual "shop drawings" at which point you should be asking your shop (and honestly shouldn't have to ask, unless you have a supervisor that can answer them)

NX8.0, Solidworks 2014, AutoCAD, Enovia V5

RE: how would a machinist program this?

Please don't multiple post rhmeng you have it here and other in GD&T and now have replies both places.

Didn't you have a similar question about dimensioning curves a few weeks back, or am I thinking of someone else?

Dimension it based primarily on functionality as JNieman says.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: how would a machinist program this?

yea sry i was looking for a reply from both ends, the engr and the mfgr. Too many times I talk to people and they just throw something on a drawing and make it the other guys problem.. they actually somewhat came to the same conclusion as far as how to dimension, saying there is not really a more correct way and just to design to the part functionality. I had a similar question a while back but I wanted input from the machinist point of view, lesson learned. Thanks.

RE: how would a machinist program this?

Most machinists can do trig way better and faster than I can, but it saves time and money to help them avoid doing any at all.
... e.g. by providing center locations for radii, and providing coordinates for tangent points. If that results in the part being overconstrained, mark some of the dimensions as reference.
... but first, if at all possible, go find the machinist who will actually make the part, and have a nice chat about how to dimension the part to make manufacture and inspection easy and straightforward.

Bring doughnuts.

Mike Halloran
Pembroke Pines, FL, USA

RE: how would a machinist program this?

Oh. Important Shop Rules:

Don't bring food or drink into a temperature controlled shop.
Don't rest drink or food on a machine way or a surface plate.

Mike Halloran
Pembroke Pines, FL, USA

RE: how would a machinist program this?

A machinist would have a print with the necessary information including what needed to be machined and the tolerances. The manufacturing engineer would have defined the methods to be used by the machinist based on additional information.
What is the material? Aluminum, cast iron gray, cast iron ductile, cast steel, cast austenitic stainless steel. Is this a cast part needing milling on the end or a flame cut part or a forged part or a bar stock part?
Is the part heat treated after machining? Is the part plated?
How many do you need to machine one, 10, 100, 10,000?

I was a N/C and a CNC programmer for 12 years and machined many different parts on many different machines. I manually and later used computer assist to program many parts and used paper tape/mylar tape. Machines today have a nice interface and many programming features built into the controls. Many of my programs were manually written and manually put on tape. Give me what you want and I can make you a program. Give me all the information.


RE: how would a machinist program this?

Our machinist respond better to biscuits, might be a Southern thang.


The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: how would a machinist program this?

A component drawing should provide all the necessary info to manufacture the part. This may mean the machinist reaches for his calculator but he should be able to work out his intersection points with the dimensions provided. But, the machinist will know the programming language and be able to create the program so it may help to know how he would prefer the profile to be dimensioned.

RE: how would a machinist program this?

Iges file, perhaps?

Proud Member of the Reality-Based Community..

To the Toolmaker, your nice little cartoon drawing of your glass looks cool, but your solid model sucks. Do you want me to fix it, or are you going to take all week to get it back to me so I can get some work done?

RE: how would a machinist program this?

The cnc programmer would import your cad drawing and use it to machine the part. If it is done by manual G code programming all the tangent points that is the angles and start and stop points need to be calculated. If that is how it is to be programmed it will help a bunch showing those calculated dimensions, and scaling up the drawing to a much larger size.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. Download Now
eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close