Finding the Right Vendor for Your Weld Fixtures

Seven questions to consider when investigating a new vendor for your weld fixtures.

If you are a the Manufacturing Engineering Manager, a Project Manager or a small business owner, you may find yourself looking for someone to design and build a weld fixture for you.  It is often cheaper than hiring and training someone to do the design internally.

Now with digital media, it is easier than ever to work with companies that are thousands of miles away from you.  Through email, and Skype, and web conferencing it is easier than ever to keep tabs on a vendors progress and communicate concerns and requirements.

But, you probably aren’t going to ask your competitors who they use.  How do you know who is good?

You can ask vendors and other networking contacts, you can search the net.  But once you locate a company you need to investigate further.

What do you do?

ASK QUESTIONS!

1) What is their history?  How long have they been designing weld fixtures?  More importantly, do they have customers who keep coming back for more weld fixtures?  How long have they been designing fixtures for that/those companies?

2) Who in their company will be working on your fixture? What is their experience in designing weld fixtures?  The person over-seeing or checking the project should have a history of working on fixtures.  Experience means they have learned over time what works and what doesn’t work.

3) Does the company you are about to hire ask lots of questions of you?  They should be asking lots of questions that will help them do a better job for you, such as your standards and particular needs on this job.  They shouldn’t be afraid to call you up with a list of questions once they have dug into a project.

4) What CAD system do they use and is that important to your needs?  Do you want CAD files or just the finished fixture?

5) Do they produce good and complete drawings? If you want 3D CAD files of the fixture, ask to see a sample of their drawings to see how complete they are.  If you wanted to make another of the same fixture but not use that vendor again, could you do it from drawings like that?

6) Can you communicate easily with them? Is there a language or other communication barrier?  Some companies figure a long term relationship and lower prices will help them recover a language and culture barrier over time.  Just know it takes time and money up front to develop good communication.  And will the people you are teaching and working with still be with that company three years down the road?

7) Will they provide you updates as the design moves along?  How often do you want to be updated?  How often do you want digital images of their progress?  Many of our customers like to get images of the rough concept, then when the design is complete except for holes, fasteners, and shims.  In a large project they like to see when sections of the project are completed.

If you still feel nervous, meet with them in person, see their shop, touch the machines they have on the floor.  Ask yourself if you would be comfortable working with these people.  Does the project manager appear organized?  Who else is working with them?

If this is your first project to outsource, you may be nervous all the way through because it is new territory for you.  That’s often the case when you try something new.  It’s like learning to drive a car.  Once you do it a few times it becomes easier and very beneficial to you.

Once you have asked your questions and answered their questions and you get a good quote from them, remember that $5 dollars does not make a winner.  If their quote is slightly higher or their delivery time is slightly longer than the next guy, call them up and let them know and see if they can meet the competition.  More often than not, they will be willing to do what it takes to get your business.   But, with that said, if it is a reputable company that has done work for other reputable companies, it probably is worth the extra $5 to get your project done right and on time.

‘Til next time,

The Queen

PS

Did you see that Rentapen was voted BizTimes Top 10 Small Business of 2012?  Thank you to our Customers, Team Members and Vendors for contributing to our success!

 

 

 

 

Your First Weldment Drawing — Six Pointers to Get You Started

Don’t panic, a weldment can be easy to detail if you just learn a few pointers and keep it simple.

Pointer 1 — Learn from the resources available to you for weld symbols.

First, know that there are plenty of resources available to learn. For example, you may not know a whole lot about welds and welding, but search the net and you will find all kinds of sites to help you for free. And there is always the Manufacturers Handbook.

For weld symbols, you can refer to this great web resource. This site shows the weld symbols and how they look.  Understanding what weld symbols to put where takes time to learn.

Fillet Weld Symbols

In machine design, usually the weldments have Fillet Welds;

 

 

 

 

 

 

OR when one side is flat and one side is curved like welding a plate to the side of a square tube;

 

OR when both sides are curved, like welding two steel tubes together.

 

See how easy it is to learn from images and text on the net? Groovy!

 

Pointer 2 — For each part in the weldment, think about what is machined before it is welded, and what is done after it is welded together.

For example, when detailing a weldment, there might be items welded together with angled cuts, like on the end of a tube or a chamfer on a gusset.  These cuts are made before it is welded.   So, it will simplify the drawing if you detail those parts separately.

 

 

This makes it easier for the shop to read a complex weldment drawing and helps them create cuts on some parts before welding them together.  Be sure to note on the main weldement drawing that there are more details and where to find them.  (ie: next sheet, or separately)

 

Pointer 3 — Never locate a part in a weldment from a finished surface! 

In the weldment drawing locate each part first.  And remember, that finished surface isn’t there until AFTER they weld it together!

In this image the .50 dimension should be used, not the .12 dimension which refers to the finished surface.  The finish doesn’t exist until after the parts are welded together.  Then the finishes and holes are added.

 

Pointer 4 — Remember, only finished surfaces can have critical dimensions. 

 

Notice, only the finished surface gets a 3-place dimension.  It is not possible to weld a part to a 3-place dimension.  So locating dimensions should be 2 place on an inch drawing (1 place on a metric drawing) .  Check your company standards.

 

Pointer 5 — After you locate the parts, give the overall dimensions of the parts. 

If you don’t have a separate detail of a part, you need to give it’s dimensions (Thickness, Height, Depth/ xyz).

 

Pointer 6 — Dimension the machining that is done after the parts are welded together.

The holes and other machining can now be dimensioned.  If the weldment is large and complex, it is a good idea to start with new views of the weldment, possibly on a new sheet.  These views will have just the dimensions for the machining done after the parts are welded together.  This makes the weldment drawing easier to read and understand.

Now you are on your way to making great weldment drawings.  The key is to just keep learning.

‘Til next time,

The Queen

6 Benefits to using Sub Assemblies in Machine Design

Discover How Sub Assemblies Save a Ton of Time and Money in Machine Design.

Sub Assemblies in machine design are fun and easy and the really help save time and money in a lot of ways.  Once you learn how to use them efficiently you will see all kinds of places that they can be used.  Then, you can be the CAD wizard at your company!

A sub assembly is just a 3D CAD Assembly that is inserted into the Main 3D CAD Assembly in machine design.  If that sentence doesn’t make sense, keep reading and watch the video below to get a good idea of how Sub Assemblies are super tools for Machine Designers.

For example these Jergens Jig Feet along with RAPid Shims and manufactured risers are used several times in a fixture.  As sub-assemblies they save time, and unclutter the assembly drawing.

 

 

 

 

This configuration of RAPid Blocks and RAPid Shims is used in several places on a weld fixture.  Only the pin changes.

 

 

 

So this configuration, without the pin, is a good candidate for a sub assembly.
It will save engineering time to create it once in a Sub Assembly and then insert the Sub Assembly into the Main Assembly several times.

 

This goal post is part of a change over fixture.  A change over means that more than one product is welded within this fixture.  To “change over” the fixture to hold a different product, one sub assembly can be removed, and another sub assembly (or cover plate) can be put in its place.

In a fixture with lots of parts, it is easier for the machine assemblers to read the assembly drawing and assemble a machine when the drawing is less cluttered.

Benefits

1)      The Machine Assemblers will love it!  The drawings are easier to read.  There are less Balloons on the Main Assembly Drawing.

2)      It is easier to job out parts of the fixture to be made by contractors or machine shops.

3)      If sub assemblies are contracted out to be made, more people can be working to create the machine at the same time, moving the machine into production faster.

4)      Faster CAD design because the same sub assembly can be inserted several times into the main assembly.

5)      Assembly model checking time is reduced because each sub assembly only has to be checked once.

6)      The MAIN BOM can contain all the parts for the whole machine, just like always.

Numbering

It depends on your numbering system.  All parts in a sub assembly get normal part numbers.  Even the sub assembly gets a normal part number.  If a 3/8” jam nut is part 103, you can use part 103 inside a sub assembly and also elsewhere in the main assembly and it won’t be a problem.  The main Bill of Material will reflect the total quantity of parts both inside and outside the sub assembly.  And the Sub Assembly Bill of Material will contain only the quantity of part number 103 used in the Sub Assembly.

We find it helpful to use the words “sub assembly” in the name or description of the sub assemblies.  That way they are easy to identify in the BOMs.  Your company may use a special group of numbers for your sub assemblies.

Now discover how to get the Bill of Material (BOM) to show all the parts but balloon only the parts not in the sub assemblies!  Watch this short video.  (The demonstration is using Pro/E Wildfire 4.0. )

So the instructions for flattening  the Bill of Materials for the purpose of ballooning only those parts not included in the sub assembly is as follows.

Steps

  • Select Table from Top Menu
  • Select Repeat Region
  • Select Flat/Rec Item from the pop-up window
  • Select the Bill of Material (Table)
  • Select Default or Flat (to flatten the Bill of Material)
  • OR Select Recursive (to expand the BOM show the parts that are in the Sub Assemblies)
  • Select the sub assemblies in the BOM
  • Click OK or “Done”

Be sure to sign up to receive Education and Updates!  All people who sign up in April 2012 will receive RENTAPEN’s DOWEL HOLE GUIDE.

Give me a Recommendation on Linked in!

View Susan Straley's profile on LinkedIn

Leave a comment below… tell me, do you use sub assemblies?  Why or why not?

‘Til next time…

The Queen

To Drive or Not To Drive Holes in Machine Design

When do YOU Drive or Not Drive Holes in Machine Design? 

When designing a fixture it is very helpful to drive the hole in part B by using the axis of a hole in part A that is fastened to part B.  And when is “Un-driving” that hole a good idea?

 

 

 

 

 

When should holes be “un-driven”?

There are two times that I can think of right off the bat where a driven hole should be un-driven.  I mean “un-driven” so that the hole in Part B is no longer dependent on Part A.

1)      The machine is already built and you are making revisions.

2)      The customer requests that holes be independent of any other parts in the assembly.

 Revisions

In revisions to a machine that is already built, it is important that the CAD Drafter keep the existing holes in the same locations.  This reflects reality and if there are future revisions to the machine, the designer knows where the existing holes are.

Sometimes it turns out that those existing holes can be used in the new revision, saving machining time and costs.   But certainly the designer needs to know where existing holes are so that they don’t design in a hole that overlaps an existing hole.

When making a revision to an existing machine, if I am going to delete Part A (the driving part), I “hard-code” or “un-drive” the hole in part B first.  In this video I show how I drive and un-drive holes in Wildfire 4.0.

Please keep in mind that Rentapen has customized the process of making holes in Pro/E.  This means that your screen and hole making steps may be different than what you see in this video.

 

Per Customer Request

 Besides revisions, some Customers can often request that holes not be driven.  They might have had a bad experience in the past or with a different program.  In really large machine designs, the large number of driven holes can slow the CAD program down.

I feel it is a risk to not drive the holes.  If the holes are not driven and a CAD Designer makes a change to a CAD design, for example:  The Designer moves Part B but forgets to move the holes in the Part A.  The result is  a costly and time-consuming mistake.   We all know that humans are not perfect and even we CAD Drafters and Designers make mistakes sometimes.  Even if the CAD Designer remembers to move the corresponding mounting holes in Part A, if there is a typing mistake, the holes won’t match up.

Though we can hope that the person checking the changes would catch the error, it is better to make sure the mistake doesn’t happen in the first place.

 

Single Fastener Parts, do you drive the hole or insert the part?

Some of our customers prefer that a flat foot or anything with a single fastener not drive the hole in the part it is mounted to.  Instead they prefer that the part be located by a hard-coded hole.  They find it easier if a change needs to be made, to change the dimensions locating the hole than it is changing how the part is defined in the assembly.

For example, should this Jergens Flat Foot be located by the hole in the gold block?  Or should the Flat Foot be located in the assembly and the mounting hole be “driven” into the gold block?

Since I am a proponent of beginning with the parts that touch the product when designing, I would put the flat foot in first, complete my design, and drive the hole in the gold RAPid Block.  Then, if I am working for a customer that prefers the flat foot be located by the hole, I would un-drive the hole, re-order the parts in the model tree, and re-define the flat foot according to the customer’s desires.

 

So tell me, does your company have a standard on whether to drive a hole from a single fastener part?  If so, what is the standard?  Do you know the reasoning behind the standard?  I would appreciate learning what you think and what your company likes.

‘Til next time!

Susan Straley
Queen of Lean Machine Design

Remember!  Sign up for Education and Updates on the Rentapen website in April 2012 and receive a free Dowel Hole Guide for your desk top!

 

 

Images of Weld Fixtures — Weld Fixture Design 101

Here are some images of weld fixtures we have designed recently. Also, at the end, is a new kind of bike to ride the Rails before they become trails. Enjoy.


 

 

 

 

 

 

Three parts are welded together in this small weld jig.

 

Top view, same fixture.

 

 

 

 

 

 

The CNC leaves an interesting pattern on this weldment.  It looks wavy, but is very smooth.

 

 

 

Small Weld Fixture using Goal Posts.

 

 

 

 

 

 

 

Robotic Weld Cell Fixture that rotates.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You can see all the  RAPid Tooling Components(TM) in this fixture.

 

Sign Up in April for DOWEL HOLE GUIDE.

Sign up for “Education and Updates” on Rentapen’s website in April, 2012, and you will receive a free Dowel Hole Reference Guide for your desk top.  Signing up means you will receive an email when a new blog or press release is posted.

Now, I would like to share this, a fun and inspiring post sent from one of our  followers:

The unstoppable passion

http://www.supertopo.com/climbing/thread.php?topic_id=1757772&tn=0&mr=0

3D Solid model
http://www.supertopo.com/inc/photo_zoom.php?dpid=Mzs-Pjk8KCAq

Fwd View 3D Concept model
http://www.supertopo.com/inc/photo_zoom.php?dpid=Mzs-Pjk4JScr

Fork Assembly in Weld Jig
http://www.supertopo.com/inc/photo_zoom.php?dpid=Mzs-PjY-IyMi

‘Til next time…

The Queen of Lean Machine Design

Product Design vs Machine Tooling Design, What’s the Dif?

What are the two main differences between product design and machine tool design?

Right off the bat I think of two main differences between designing a product and designing machine tools.

TIME and DIMENSIONS

TIME

Product Design Time


When designing a product there may be numerous design reviews, you may spend a whole year or longer between conception to tweaking the design, testing it for market appeal, functionality, safety, costs… the list can go on.  And many of these reviews don’t happen just once.

Then, when the product gets very close to completion, the manufacturing team starts planning for production.  What parts will be assembled at what stations.  And the Manufacturing Engineers and Managers start working on planning the design of the production machines.

Machine Tool Design Time

calendar-machine-design

Once the product is getting close to release for production, there is a rush to get the machines, designed, built, and tested fast.  The time line for a Machine can be as little as 1 month.  Some of the more simple tools are created on the fly as the product moves into production and the need is discovered.

 

With Machine Tool Designs there may be only one or two design reviews.  There is no need to make it look nice for the consumer, though safety and functionality are part of the design and review process.  The whole machine design process doesn’t require as much time or as much… “going back to the drawing board”.  (For those of you who are too young to have ever seen a drawing board, what I mean is in my experience there isn’t as much re-design occuring in machine tool design as in product design.)

DIMENSIONS

One thing I hear from those who move over to machine tool design from product design is that in machine design the available stock size matters.

part-dimensions

 

 

 

 

With each new manufactured part you need to think about using nice numbers so that the part can be manufactured easily with the least number of surfaces having to be finished.

A machine tool designer is always looking up stock sizes.  And every time the designer has to change the size of a part they have to think about stock sizes and which surfaces will need to be finished.

When a machine designer can avoid finishing a surface, he/she saves build time and material, reducing the costs of the machine.  So we must always check our stock sizes, and try to make the mounting surfaces stock dimensions. This way we avoid having to machine a nice mounting surface if we don’t have to.

When a piece of metal is saw cut, the surface is very rough and may not be square to the other surfaces.  So mounting surfaces need to be stock or finished in most all applications.

Hot Rolled Steel is so rough even as stock, it needs to have all it’s mounting surfaces finished.  We use Hot Rolled Steel for weldments only, and cut a minimum of a 1/8 inch off the stock size to make a nice finished surface for mounting other parts onto.  We still make every effort to consider stock size when creating weld fixture parts.

Two companies that we refer to a lot to find out what stock sizes are available are Central Steel and McMaster Carr.


http://www.centralsteel.com  for cold and hot rolled steel and aluminum and sheet metal.  They have angles, tubes, rounds also.

 

http://www.mcmaster.com for harder steels or other metals not found in the Central Steel catalog such as A2  and 4140 PH (Pre-hardened).

So Product Design vs Machine Tool Design.  If you have experience in both, what differences have you noticed?

RECEIVE a FREE Quick-reference Tool on Dowel Holes.

Anyone who signs up for “Education and Updates” … in April 2012 ….by filling out the form on the right-hand side of the Rentapen web site will receive in their email Rentapen’s Quick Reference Guide to Tolerances for Dowel holes.  This is a handy item to keep on your desk top.  So sign up today for “Education and Updates”.   We email updates when we issue or new blog or press release (about twice a week).

What Where and How of Metal Shims

What, Where, and How of Shims and Shim Packs

I am excited about our new Free 3D CAD Models ordering service on Rentapen’s web site.  I know I promised to talk more about the simple weld fixture (weld jig), this week,  however I am delaying that because this is (I think) so COOL!!

Our line of tooling components are now even easier to use.   I invite you to play with this new 3d model downloading service.  These files are Free!  Since we are still discovering kinks, be sure to let us know if you find any problems.

The videos I have for you today are about how to use this service.  But there is so much more to learn. These videos aren’t polished, but you will get the idea.

First, I talk about shims and show how they are placed in a real fixture. You might want to turn the volume down a bit, I start in the shop…

I know I go on and on about shims at times. I am a big advocate for shimming in weld fixtures.

With so many variables involved in how much heat will be created during welding and therefore, how much distorting will occur on the product being welded, shims and shim packs are essential. They help the production group set up the fixture before full production begins. So that when the weld jig or fixture goes into full production it is putting out a product that works.

In this next video I  show you how to download a file for a RAPid Block(TM) and a RAPid Riser(TM).

And in THIS video, our team member, Kory, tells you how to get your Pro/E parameters into your STEP file.

 

I hope you have fun trying out the new 3d models and seeing how you can use them. I’d love to see what you come up with! Didn’t you like playing with legos??

Send images of your designs using RAPid Tooling Components to news@rentapen.com

The Queen of Lean Machine Design

 

Weld Fixture Design – Discover how to Adjust Location of Straight Action Clamp

Discover how to adjust the location of a straight line action clamp.

Often times, when designing a fixture we need to think ahead to where else adjustments might be made that will affect the area of the design we are working on.

In this video lesson we discuss using RAPid Plate ™ RB09 in combination with metal shims and over-sized holes to locate a straight line action clamp sub assembly.

So in this lesson we talked about sub assemblies. We have found them very useful.  In a future blog I will talk about how to create them, use them, and still have your whole BOM shown on the main assembly drawing.

Now, those of you who read this blog have a special treat.  Rentapen has just launched it’s beta for downloading 3D models of RAPid Tooling Components.   Please help us test it out and leave a comment below. Go to Rentapen’s home page http://www.rentapen.com and click the last item in the top menu, “Order 3D Models”.

Let me know what you think!

The Queen

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