The Diamond Pin, The Shoulder Screw, and The Bushing-Weld Fixture Design Lesson

Now that we have a Diamond Pin that is only touching the part on the top and the bottom of the pin, we need to make the contact points of the pin remain in the same up and down orientation.

To say it differently, we have to make sure the diamond pin doesn’t rotate.  We can do this with a flat cut on the pin and a shoulder screw mounted next to the cut.  Let’s take a look at the video…

 

Thanks for joining me as we learn together. I hope you are having as much fun learning as I am!

Next week we will talk about how this sub assembly is shimmed and mounted.

The Queen of Lean Machine Design

Using a Pin for Orienting vs Locating

We are continuing our discussion of the use of a Straight Line Action Clamp in a weld fixture.

The purpose of the clamp in our sample fixture is to move a locating pin into a hole in the product part to locate.  Then, after the product is welded, the Straight Line Action Clamp can retract the pin, so that the product can be removed from the weld fixture.

In this weeks blog video, a round locating pin is replaced by a diamond pin in our sample fixture. using a straight line action clamp. Instead of locating the customer’s product in the weld fixture, we have changed the purpose of the pin. It is now only orienting one product part with respect to the other product parts to which it will be welded.

Next time we will be talking more about this diamond pin and the bushing block it is moving in.

There is a form on the right hand side of our website where you can sign up to be notified of education and updates. When you sign up we will will send you an email each time a new Weld Fixture Design 101 lesson is posted.

Thanks for learning with me.   Please feel free to leave your comments and questions in the comment section below.

The Queen

Cost Saving Clamp Risers

Lean Manufacturers Are Now Saving Time and Money By Purchasing Their Clamp Risers Through Rentapen Inc.

Rentapen’s design team has been designing machines for 35 years. They realized they were designing the same clamp risers over and over again. So Rentapen developed what is now called Rentapen’s RAPid Tooling Components™, a line of tooling components.

These standardized yet versatile components save manufacturers time and money.

The mounting holes in the clamp risers are able to fit a wide variety of brands and sizes of clamps including:Carr Lane, REID, De-Sta-Co, TE-CO, All American, and Jergens. A catalog of choices can be found on Rentapen’s website.

If a designer created a clamp riser from scratch, like Rentapen and all other machine tooling design companies used to do, they would have to go through a timely and expensive process that includes: designing the part; detailing; checking; ordering material; writing the CNC code; creating the part and finally inspecting the part.

The whole process takes about 77 minutes. Manufacturers will soon be able to download the 3D model from Rentapen’s website, save the model to their library, put the riser into their design, and order the block. This approximately takes 4 minutes. Rentapen’s RAPid Riser™ is saving the manufacturers as much as 73 minutes in design and build time.

 

Rapid Tooling Components™ reduce the design cost of the fixture by eliminating the need to design, detail and check similar parts over and over again. Three dimensional computer models are provided by Rentapen that customers can use to incorporate into their designs.

Clamp Risers come in .5 inch increments and in aluminum to reduce weight in the fixture.

“Rentapen is theUSleader in machine design and tooling components. We earn our customer’s enthusiasm because we enjoy the opportunity to provide efficiency by design, expertise, and convenient service,” said Susan Straley, Queen of Lean Machine Design and President of Rentapen Inc.

Manufacturing engineers have known that purchased components save time and money. Manufactures have been buying their clamps that hold their product parts in position while they are being welded or assembled. Now they can buy their risers that sit under those clamps from Rentapen and reduce their costs.

 

 

 

 

 

Jig or Weld Fixture Design — Holes 101

In machine design there are fundamental rules to follow when locating fasteners.  I remember taking drafting classes but I was taught the basics of holes and hole locating only after I started working for Rentapen many years ago.

Mr. Iyer commented on the blog last time that I didn’t talk about construction holes for locating the angled cut on the v-block. He is right! So this video talks construction holes. I just want to add that in the video I put in .313″ construction hole. Looking back at it, a .25″ would have been better for this small part.

Also the video today talks about a major rule of thumb for locating mounting holes.

Mr. Iyer’s comment talked about using a plane that goes from the construction hole to the dowel hole that was zero/zero in the other surface. If this helps, where should I locate the other zero that is normal to that one. Also at the original surface dowel?

Remember, nothing is written in stone here. So if you know a better way or your company does it differently, share that with us in the comment section below!   Are there other rules of thumb you can share?

MORE TO LEARN!

A reader of this blog, Marvin Davis, has shared with us some links to other free education.  It doesn’t appear that any of them are on machine design, but some are on computers and math and so might be of interest to you.  I am sharing the list below.  But before you leave us to surf and learn, be sure to sign up for Rentapen news and updates on the right side of this page.  Then you will be notified of the next Weld Fixture Design 101 blog.

 

The Really Free Schools are Onlinehttp://www.independent.co.uk/life-style/gadgets-and-tech/features/the-really-free-schools-are-online-2353052.html

 

Berkeley Webcasts

http://webcast.berkeley.edu/series#c,s

 

CERN Document Server

http://cdsweb.cern.ch/

 

Harvard Open Learning Initiative

http://www.extension.harvard.edu/open-learning-initiative

 

Houston – University of Houston

http://www.youtube.com/user/UHouston#g/c/4F8EC29025F10C20

 

Indiana Multimedia Distribution System

http://www.imds.iu.edu

 

iTunes U

http://www.apple.com/education/itunes-u/

 

Khan Academy

http://www.khanacademy.org/

 

Math On Line – University of Colorado Colorado Springs

http://www.uccs.edu/~math/vidarchive.html

 

Mathematical Sciences Research Institute

http://www.msri.org/web/msri/home

 

MIT Open Course Ware

http://ocw.mit.edu

 

McGill Courses On Line

http://cool.mcgill.ca/

 

nanoHUB

http://nanohub.org/

 

Open Learn – the Open University

http://www.open.ac.uk/openlearn/

 

Oxford Podcasts

http://podcasts.ox.ac.uk/

 

RSA Animate

http://comment.rsablogs.org.uk/videos/

 

Scribd – Social Publishing

http://www.scribd.com/

 

Stanford Engineering Everywhere

http://see.stanford.edu/see/courses.aspx

 

Video Lectures

http://videolectures.net/

 

Yale – Open Courses

http://oyc.yale.edu

 

YouTube – Education

http://www.youtube.com/education

 

 

 

Rentapen Continues To Expand

Rentapen Inc. located in Waukesha, WI just hired a Shop Maintenance Associate and Customer Order Manager

Rentapen’s team continues to grow in order to support their mission of helping manufacturers reduce costs. Rentapen has added two new employees to their team, Vicki Treul and John Edward Murphy. Treul is the new Customer Order Manager and Murphy is the new Shop Maintenance Associate.

Treul will be responsible for 2D drawings of parts for quoting, inventory control, and creating files that will be sent to the metal cutting laser as part of Rentapen’s Just-in-Time Laser Cutting Services.

“Vicki Treul’s extensive background and skills in production management, will contribute to Rentapen’s growth,” said Susan Straley President at Rentapen Inc.

Murphy will be in charge of all the maintenance in Rentapen’s CNC machine and metal cutting lasers and other factory equipment. Murphy will be taking care of all the machines, assembly, cleaning, packaging, and assisting all the employees that work in Rentapen’s factory.


“I’m excited to join the Rentapen team and I’m happy to see the company grow,” said Murphy.

“Ed has experience in machine maintenance and along with a good work ethic, he fits right into our culture,” said Straley.

Rentapen’s CNC machine and Laser Cutting machines are used for producing Rentapen’s RAPid Tooling Components, a line of blocks, plates and clamp risers and shims used to reduce the costs of jigs and weld fixtures.

Rentapen’s larger, metal-cutting laser is used for Rentapen’s Just-in-Time Laser Cutting Services. Rentapen has a Mitsubishi 4000 Watt CO2 laser that cuts up to 1 inch steel, .5 inch stainless steel and .5 inch aluminum. The laser table will accommodate a sheet size of 5ft by 10ft.

The key benefits of Rentapen’s Just-In-Time Laser Cutting Services are a small affected heat zone, repeatability, close tolerances, and speed of cut. The cutting feed rates for Renatpen’s laser are ½ inch of aluminum is 200 inches per minute, 1 inch mild steel is 100 inches per minute and 1 inch of stainless steel is 100 inches per minute.

Rentapen’s Just-In-Time Laser Cutting Services can help manufactures reduce their inventory costs because they can order only what they need when they need it.

Jig or Weld Fixture Design – Locating Round Tubing

In this lesson on Jig or Weld Fixture Design we are going to discuss round tubing. 

I can think of three ways to locate a round tube off the top of my head.  That doesn’t mean they are the only ways.  You might be able to think of other ways.  So share any ideas you may have down in the comments section, or email me at straley at Rentapen.com and attach pictures or jpgs so I can share them in future blogs.

V-BLOCKS

We often use v-blocks to hold round rods or tubes.  A v-block is simply a block with a v cut into it.

If I need to design in adjustment with shims, I often will sketch on paper a rough plan. 

Sketching an adjustable V-block

If I am able to use purchased products, like RAPid Tooling Components to locate the V-block, I will sit with the catalog next to me and decide which blocks will work so I can pull those models from the library. 

 

A sketch helps me think about which blocks will have the slip fit dowels and the tapped holes and which ones will have the press fit and the counter bores. 

 

This video kind of explains what I have sketched. 

 Another popular way to hold a tube or rod in place in a jig or fixture is with a goal post. 

Consider the material that the tube is made of and how much use the fixture will get when deciding what material the plates should be.  The plates above are RAPid Tooling Components™.   These plates come in hardened steel (4140 PH) and Ampco 18.  Remember that weld splatter sticks to like metal.   Aluminum sticks to aluminum, steel to steel, etc.   So if you are welding steel, the Ampco Bronze may be a better choice for the plates of the goal posts. 

 

Sometimes the best way to hold a tube is with a pin that is inserted into the center of the tube.  The best method depends on the application, the size and length of the tube,  and your customer’s preferences

 Here is a little video that goes over some of the ways to locate a round tube or rod.

What have YOU done in the past that worked that I have not discussed here?

 

 

Jig or Weld Fixture Design – 12 Questions

What do YOU ask before you begin your Jig or Weld Fixture Design?  Here are some questions to start the discussion.

When you are presented with some product parts and asked to design a fixture or jig so they can be welded together,  what questions do you need answered before you begin?   It is important to get as much information on the project as possible before you even do a rough sketch.

For example:

1) How many parts will be welded together in this one fixture? 

The production planning team will need to figure this out.  The more parts they can fit on one fixture, the less fixtures and operators they will need.  However they need to take into account that if one station in the factory takes longer than the rest of the stations they will be creating a bottle neck that will slow the whole production line.  That could be fixed by having two of the same fixture, or by reducing the number of parts welded together in one fixture.

2) Is there another product line with very similar but different parts that could be welded together in the same fixture with a quick change over?  

Sometimes a fixture can be used for several products.  Just replacing one or two sub assemblies can quickly create a fixture that can run two or more products.    In a future blog we will delve into the different gizmos and tools you can use to make the change over fast and easy.

V-Blocks for two product lines

Designing for two product lines sometimes is easy.

 

 

 

 

 

 

 

 

 

3) Will the fixture be automated or manual? 

Will you be using pneumatic clamps or manual?  What about sensors that will sense if the part is in place before clamping or before beginning the welding procedure?   Will there be forward and back checks?

At Rentapen, our 3D models will show the placement and mounting of the sensors and clamps.  The design must allow for room for the hoses and wires.  At Rentapen we leave the design of the controls and electrical to the experts.  We focus strictly on the mechanical aspect of the fixture.  It is important to you and the team that there is a clear understanding of where your responsibility lies.   Tasks for who is responsible for what parts of the fixture (jig) or robot cell should be clearly laid out before  you begin the design.

4)  Will the fixture be trunion or table mounted? 

Will it be robotically or manually welded?  If it is robotically welded, what are the dimensions within which the fixture must fit?

5)  When is the project due? 

When should the preliminary design be ready for review?  When should the checked drawings be completed?  Is there a set schedule?

6) Where are the welds?

The answers to these question should be on the weld drawings for the product.  Usually, in a well planned out line, there is a product drawing of the sub assembly produced in the fixture that you are going to be designing.  Study the drawing for the location of the welds.   If there is no such drawing, ask!

7) What are the critical dimensions?

Study the drawing and identify those dimensions that are held to a tighter tolerance.   If there are no tight tolerances between welded parts, then the fixture may not require shimming.   It doesn’t hurt to ask to make sure.  Asking before you begin is much more efficient.

8)  Are there parts that could be put on the fixture wrong?

Study the product assembly and see if you may need to error proof the fixture so that the parts can only go into the fixture in the way they are supposed to.  We don’t want them welding something on backwards.

9) Do you have a list of preferred vendors?  Some manufacturers prefer Destaco or Parker for their clamps.  The larger companies always have a list of the vendors they use and the products they like.  For example, Genesis Systems requires all their vendors to use Rentapen’s RAPid Tooling Components (TM) wherever possible to reduce the costs of their weld fixtures.

As a design service company, Rentapen has even more questions to ask.

10) What are your design and detail standards?

We want to match the customer’s standards as best as possible.   We put the drawings on the customers format, and follow their standards.  We ask for samples of good drawings so that we can see how holes are called off and slots and chamfers are dimensioned.

11)  Do you put more than one detail on a drawing?

Some of our customers put everything on the same size format and put as many part details as will fit on D size sheet.   Other customers limit it to four details on a D size sheet.  And some customers like to have each part detailed on its own sheet.  A B C D or E.

12) How often do you want status updates?

For smaller fixtures, you will design it up and only have them look at it once before you start detailing it.  But for larger projects, usually the customer will want to see your progress once a week, or as you complete the design for each section of the fixture.  I use the term customer to mean who you report to, who you are serving, be it your production planning team or your manager … whoever your customer is.   As a fixture designer the best way to reduce costs for your time is to get feedback on your designs before you go too deep.

What questions have I left out?  What else do you ask? 

Please add to the conversation and let me know what you think!