asu design and manufacturing booklet

8/13/2019 ASU Design and Manufacturing BOOKLET

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ASU Designing For All ManufactureDennis Golabiewski

[email protected]

General Comments

Successful mechanical design requires several factors to be brought under consideration.

The following are some of those issues you will need to consider and understand about

the design process, as it relates to the machine shop, before submitting projects to the Ira

A. Fulton School of Engineering Development Machine Shop:

Design scope, intent and complexity.

Considerations:

Time to completion (shop time is our concern here). You need to remember that yourdesign time can be only a fraction of the time it will take to manufacture a part. If it takesweeks to design, it may take even longer to machine.

Cost: materials and specialty tooling in the shop. Labor is no charge. Design: complexity and clarity greatly affect job completion time. Shop Backlog: varies during the year. Design, engineering, detailing and manufacturing tools: use (CAD/CAM, FEA, CAE) Staff experience: There are varying degrees of expertise and backgrounds

in the shop. This as well as work load may result in a variation of the actual time quoted forpart production

Intelligent Design Guidelines and conveying Design Intent.

Employ the "KIS" principle (Keep It Simple), simple designs almost always result in functionalparts and assemblies as well as generating a quicker turn-a-round)

ASSEMBLY NOTE: For each assembly component, there is opportunity for incorrectly designedcomponent/assembly interference. As the number of components increase, the material cost and time for fabricating theproduct increases. Tolerance accumulation (stack tolerances) becomes more significant and may require additionaldesign considerations to produce functional assembly components. Additionally, creating design documents andmanufacturing processes are additive. As the product structure and required operations are simplified, fewer fabricationand assembly steps are required, manufacturing processes and lead-times are reduced. The designers, researchengineers and manufacturing engineers should review all components within an assembly to determine whethercomponents can be eliminated, simplified or combined with another component or the function of a design can beexecuted with a simpler approach. Remember these are engineering functions not machine shop functions. The shoppays machinists to make parts not design them! Always have your designs proofed by at least one other engineer.

Design using off the shelf,standard or OEM components to simplify the design andmanufacturing process. (we do not manufacture parts you can purchase)To minimize the amount andvariation in common components and to insure standard replacement part availability check forreliable suppliers. Standard components will insure reduction in manufacturing time and result inreliable quality. Standard component design charts (availably on the internet) can be used toexpedite efficient design. Some suppliers do offer CAD files of the components they sell.Downloading these files is useful even when modifications are required for off the shelf parts.Manufacturing is simplified and production brought to the foreground quickly.

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Design for ease of fabrication and assembly. Know about the manufacturing and machiningprocesses in your design, understand the materials and production requirements. Selectmaterials compatible with production processes and that minimize processing time while meetingfunctional, realistic design requirements. Avoid unnecessary part features. They involve extraprocessing effort and/or more complex tooling. If you want it to look pretty, paint it later!

Machine Shop Equipment and Tooling

The following list covers most of the machine tools and equipment utilized in the Ira A. FultonSchool of Engineering Development Machine Shop.

Manual Milling Machinesare used to drill, ream, bore, counterbore, countersink, lap and tapholes. Mill 2D profiles and pockets. (accuracy to 0.002, Operation dependent)

Manual Engine Lathesare used to drill holes (on centerline of rotation, (turn) machine ODs(outer diameters), bore IDs (inner diameters), face (cutting the end of a piece flat) groove (cutslots or steps on the ID or OD of a piece, cut or chase threads on the ID or OD of a workpiece

and machine both ID and OD tapers up to 10 degrees. Although cylindrical or conic workpiecesare the majority of work done on lathes it is possible to cut rectangular pieces or holes inrectangular pieces. (accuracy to 0.002)

Surface Grindersare used to machine extremely flat and smooth surfaces. They machine partsflat, parallel and square to a very high tolerance. Some materials cannot be ground do to theproperties of the material. (accuracy to 0.0005)

Cylindrical Grindersare use to machine high tolerances on cylindrical or conical shaped pieces.Both the OD and the ID of this type of piece can be machined. (accuracy to 0.0005)

CNC Milling Machineshave all the functionality of manual milling machines plus some very

important added capabilities. Because the movement of the machine is now controlled by acomputer and servo motor control cards rather than the machine tool operator additional complexfeatures or surfaces can now be machined. The CNC mills at ASU are capable ofsimultaneous/independent 2, 3 and 4 axes movement. This allow for machining of complex 3dimensional surfaces. Such surfaces as are found in parts like air foils, impellers, gears anddouble helix screw designs to name only a few. CAD files are directly imported from your datafiles submitted to the shop. CAM (computer aided machining) software is then used to preparesurfaces for machining and generation of computer code (G-code) the machine tool canunderstand.

CNC Lathesare also capable of performing all of the operations done on standard manuallathes. There are additional functionalities found on CNC lathes. The process of importing datadirectly from completed data design files is the same as that done with CNC mills. With that in

mind we now have the ability to cut sculpted surfaces on cylindrical and conical components aswell as tapered or double helix threads.

Other Machines and Equipment in the Shop

Radial rm Drill Press Pedestal Drill rbor Press

Shear Brake Broach Hand Tools

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Machining Processes

Threaded (tapped) Holes

Design for full thread depth. Usually 1 - 2 times the major diameter provides adequateholding strength (this will be different for each application and material).

Drilled hole depth (to the sharp point of the tool) is recommended to be at least equal tothe full thread plus major diameter, but never less than .050"

Material thickness as measured from the bottom of the drilled hole to next surface shouldnot be less than the diameter of hole or not less than 1/16.

When design functionality allows, thru holes are always preferred. (drilling op. only)

Drilled Holes

The standard maximum depth for a drilled hole is generally no deeper than 3 - 5 timesthe diameter of the hole.

The accuracy of a drilled hole is generally 0.005 depending on the quality of the toolingand the skill of the machinists

Drilled holes are usually clearance or placed on a part to reduce weight. They may alsobe precursors to subsequent operations.

The finish on drilled holes is somewhat rough. The larger the drilled hole the rougher thefinish.

The denser the material the larger the minimum diameter of hole that can be drilledin it.

(in general) Drilling is one of the fastest material removal operations performed in our

machine shop. Drilling not only varies in accuracy of diameter but also in absolute dimension location

and concentricity. .

Reamed or Bored Holes

The standard depth of reamed or bored holes parallels that of drilled holes

The diameter accuracy of a reamed hole can be as good as 0.0005. The diameteraccuracy of a bored hole can be as close as 0.0001. This varies with the age of themachine tool, the quality of the tooling and the skill of the machinists.

The finish on reamed and bored holes can be from 200-240 micro-inches (see chartbelow). Again the same variables mentioned early apply.

Lathe Turning, boring, parting, threading, slotting and facing

Turning is the process where material is removed from the outside of a cylindrical orconical piece mounted to the head stock of a lathe. The degree of accuracy willdependant on material, diameter and machine tool. (accuracy to 0.0005). This isoperation specific and does not apply across the board!

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Boring is the process of removing material from the inside of a cylindrical or conical piecemounted to the head stock of an engine lathe. The degree of accuracy will dependant onmaterial, diameter and machine tool. (accuracy to 0.0005).

Threading is the operation where threads are cut either internally or on the OD (outerdiameter of a cylindrical or conical piece. (NOTE)There are ways to thread on machinetools other than lathes.

Facing is the operation used to flatten the end of a piece mounted to the headstock of alathe. It should be known that the piece does not have to be a cylinder or conical inshape to be faced off.

Slotting is the operation that cuts grooves in the OD or ID of a piece on the lathe.

Parting is simply separating a finished piece from the stock being held in the head stock.

Lathe finishes parallel that of milling and some grinding finishes. See Micro finish chartbelow.

Material Finish Chart

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Examples of Perishable Tooling (cost to customer)

Perishable Tooling(cutting tools) varies from machine type to machine type. Some tooling canbe used on both lathes and mills. For example, both lathes and mills use drills (drill bits),reamers, boring tools, taps and single point cutters. Some tooling is designated for specificmachine tools only.

Lathe tooling

cemented carbide lathe bit boring head (precision hole lathe/mill) inserted carbide

Mill

Tooling

Tapered engraving end mill

.2 flute finish end mill (heavy metal removal) 2 flute finish ball end mill

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rotary carbide files (light metal removal)

taps (for internal threads) Drill bit, rough holes

adjustable reamer (size holes) broach set (cut keyways) grinding wheels

To view additional metal cutting tools search the internet for (metal cutting tooling)

The tooling above is a very small sample of the perishable tooling used in a machineshop. The more you understand the types of tooling and the machine tools used in the

material removal process the more realistic your designs can become.

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Common Machine Tools

Radial Arm Drill Press Pedestal Drill Press Band Saw

Surface grinder Horizontal knee mill

Standard Engine Lathe

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Materials and Material Selection

Material selection is an important part of your design. Often times students, research assistantsand even researchers will submit drawings without making a material call out. When ask whatmaterial is needed the answers vary and are usually pretty humorous, It doesnt matter or a

generic answer like steel. Remember, if it doesnt matter, Im making it out of wax! It cutsreally easy.

The shop requires that all drawings have a call out for material and that the call out should bespecific. There are thousands of types of steel, aluminum and plastic available. Were sure thatin many instances your project requires materials with specific properties. You will need toconsider what properties are relative to the functionality of your parts. You can find a listing of

ALL materials and all their properties at www.matweb.com. You must register at this sight but itis free of charge. The single most important property the machine shop concerns itself with is themachinablity of the material. There are some materials that cannot be machined in our shop. Ifnecessary the work can be sent out to a facility with the equipment to machine your parts butremember, you will be charged.

Manufacturing considers and general design guidelines:

For high volume parts, consider castings (molds), extrusions or other volumemanufacturing processes to reduce machining and inmachine time. This would requirethat the job be quoted off campus. (various types of mold can be built on campus) Thereare videos at the shop you can check out for molding techniques you can do yourself.

Consult with manufacturing engineering to determine and design for solid mounting or

other fixture-locating features on the component. This is usually a function of the shopbut you may be required to participate unusually if there are additional materials to bepurchased.

When designing avoid thin walls (depth should not exceed 1 thickness of wall), thinwebs, or similar features may result in distortions due to manufacturing and materialstress migration.

Avoid undercuts that will require special operations, tools or outside quotes.

Always design around standard cutters when possible, drill bit sizes or other tools (metricor english)This requires you know at least the basics of machine tool usage and the cutting toolsfor them. All the information you require can be found on the web. Check

www.engineersedge.comand www.howstuffworks.com. There is an immense amount of

information that will aid you.

Avoid small holes and threaded features (design for nut and bolt assembly). Small holes

(under 1/16

) cause the extreme difficulty when machining. Remember when designing try to use standard fractional or metric sizes.

Manufacturing tooling employs these standard sizes in the manufacture of tooling.

Non-standard(nominal) sizes may result in a substantial costin the production

of your parts.

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TIP:

Fixture/tooling and structural support material selection

When designing large steel fixtures, support structures or tooling where high accuracy flatness,perpendicularity, parallelism or true position is required, specify a material such as one of the low

carbon HRS (hot rolled steels). This material is very stable and will retain form better than CRS(Cold Rolled Steels). If large amounts of material are removed from your billet remember to callout for stress relieving prior to finishing the parts.

Dimensional Tolerancing

For surface composite curves such as, internal pockets or other profiles in CNC manufacturing acontinuous cutting path will be established and manufactured. Design for and specify symmetricaltolerances (+/- .XXX) when possible.

Reason: Often the machine tools used in the manufacture of components utilize a feature called "CutterCompensation". This allows +/- size control variation of the features being machined without having to control the NC(numerical code) program (data file) to an exact match with the cutter diameter. For a continuous path, if "X" dimension

has +0, -.005 and "Y" dimension has +.005, -0 tolerance specifying the cutter compensation cannot be used to controlsize, because adding or subtracting from cutter path input automatically invokes an error to the dimension of the othertoleranced continuous path surface. Simply, a offset is input into the machine relative to the cutting tool to manufacture formid tolerance of surface "X" at -.0025 however; this path is not compatible with the "y" surface in that the nominal offset is.0025 out of tolerance. This is also a problem when dealing with jigs, fixtures or inspection gages. Understanding thiscould drastically reduce programming and re-programming time.

If a dimension is not toleranced the following tolerances will beapplied to that dimension!

Shop defined standards will be used by the machine shop

1 place dimensions 0.015




The degree of your tolerances should be within manufacturing capabilities of the

development machine shop. The degree of accuracy for our equipment was discussed during

the orientation walk through and listed above. Do not use tolerances beyond those needed

to make your parts functional! If you require closer tolerances than we are able to produce

the work can be quoted for off campus completion. This would be at your expense.

Concurrently designing for manufacturing will greatly improve product quality and reducefabrication costs and complications. Consult with manufacturing early in the design process. Aftercompletion of preliminary drawings, meet with manufacturing and review design plausibility,requirements and determine manufacturing process requirements. Manufacturing should reviewtolerances and determine process capabilities to meet dimensional limits. Manufacturing shouldidentify tolerance challenges that require design reconsiderations.

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In general, designers should avoid unnecessarily tight tolerances. Especially those that arebeyond the natural capability of the Development Machine Shops manufacturing processes.Tolerance stack-ups should be considered on mating parts. Overall assembly tolerances shouldbe calculated, and interference as well as clearance requirements understood. Surface finishrequirements can be established based on actual manufacturing processes. However employed,surface finish requirements should be understood and the designers intent accurately defined. (ifyour know the correct use of GD&T them use the symbols)

Simplify design and assembly so that the assembly process is instantly recognizable.Components should be designed so that they can only be assembled the correct way (called foolproofing); they cannot be reversed. Roll pins, dowel pins or offset mounting holes can beemployed but should be labeled for functionality understanding on the manufacturing floor.

Remember that all design drawings must meet these very simple requirements.

All drawings must be to scale and the scale must be called out in the title block. Drawings can be in either English or Metric notation but the two cannot be mixed

in one drawing unless both are called out on every dimension.

All drawings must be done using standard third angle projection. Drawings should contain enough view to fully define the part Drawings need to be dimensioned from DATUM. ( start points ) As the designer

it is your responsibility to make the decision on where to locate your datums foreach view. Datums are generally chosen by functionality of a feature. ( edge orhole )

All drawings must contain a specific material call out. All drawings need a quantity call out or only one will be produced. Hole features should be labeled to avoid confusion as to the function of the

feature. CAD drawings must be submitted as both data file and hardcopies. (part files

must be included)

Drawings done by hand must meet the same detailing requirements as CADdrawings.

Solidworks is the School of Engineering standard. It is available for to all facultyand staff as well as students. If you are using a different CAD system checkwith the shop to determine the type of data file you will need to export to. Wehave direct translator for most major CAD systems.

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Example

Design for component orientation and handling to minimize non-value-added manual effort,ambiguity or difficulty in orienting and merging parts. Basic principles to facilitate parts handlingand orienting are:

Parts should be designed to consistently orient themselves. Examples are the use of offset dowelpins.

Product design should avoid parts that can become tangled, wedged or disoriented. Verify clearance for assembly tooling such as hand tools, screws, nuts and bolts.

With hidden features that require a particular orientation, provide an external access feature, that isto say provide access to hidden internal components in assemblies.

Design in fasteners large enough so that are easy to handle and install as well as provide the levelof functionality you require.

Special Issues

Flatness

Flatness should be applied with reasonable overall form tolerance as a means to prevent abrupt

surface variation within a relatively small area of the feature. Depending on material thicknessand application, a note can be added to a design drawing: "Consider that FLATNESS MAY BEMEASURED WITH COMPONENT IN RESTRAINED CONDITION".Where applicable, notesshould include specific restraining requirements or the lack of them. Extreme flatnessrequirements add substantial cost and time to the production of the part.

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Internal Radii

Always specify the largest radius possible. Small diameter tools add significant cost andtime to the manufacturing process and may be impossible to do in our shop.

When depth exceeds 2 xs

the diameter of the pocket corner radii, consultmanufacturing on alternative fabrication methods. Depths of up to 5 xs are possible

when machining soft metals and plastics but you still need to consult with the shop tomake sure your design is possible.

For deep sharp corner cutouts that require broaching or EDM, specify radii max at allcutout corners i.e. (4xs R .008 MAX) Remember in most instances this work will be sentout for manufacture and you will be billed for the additional costs.

Design for efficient joining and fastening, know your hardware. We do

not know what a whatchamajiggie is.

Threaded fasteners (screws, bolts, nuts and washers) can be time-consuming to assemble.Consider design alternatives that will reduce fastener count. Use uniform screw sizes where

practical. WE DO NOT SUPPLY or Build HARDWARE (items pictured below).

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Decimal Equivalents

English Metric Decimal English Metric Decimal English Metric Decimal English Metric Decimal

.. .1 .0039 45 .. .0820 5 .. .2055 7/16 .. .4375

.2 .0079 44 .. .0860 4 .. .2090 29/64 .. .4531

.. .3 .0118 43 .. .0890 3 .. .2130 15/32 .. .4687

80 .. .0135 42 .. .0935 7/32 . .2187 .. 12. .4724

79 . .0145 3/32 .. .0937 2 .. .2210 31/64 .. .4844

1/64 .. .0156 41 .. .0960 1 .. .2280 1/2 .. .5000

.. .4 .0157 40 .. .0980 A .. .2340 .. 13. .5118

78 . .0160 39 .. .0995 15/64 .. .2344 33/64 .. .5156

77 . .0180 38 .. .1015 .. 6. .2362 17/32 .. .5312

. .5 .0197 37 .. .1040 B .. .2380 35/64 . .5469

76 . .0200 36 .. .1065 C .. .2420 .. 14. .5512

75 . .0210 7/64 .. .1094 D .. .2460 9/16 .. .5625

74 .0225 35 .. .1100 1/4 .. .2500 37/64 .. .5781

. .6 .0236 34 .. .1110 F .. .2570 .. 15. .5906

73 .. .0240 33 .. .1130 G .. .2610 19/32 .. .5937

72 .. .0250 32 .. .1160 17/64 .. .2656 39/64 .. .6094

71 .. .0260 .. 3. .1181 H .. .2660 5/8 .. .6250

.. .7 .0276 31 .. .1200 I .. .2720 .. 16. .6299

70 .. .0280 1/8 .. .1250 .. 7. .2756 41/64 .. .6406

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69 .. .0292 30 .. .1285 J .. .2770 21/32 .. .6562

68 .. .0310 29 .. .1360 K .. .2810 .. 17. .6693

1/32 .. .0312 28 .. .1405 9/32 .. .2812 43/64 .. .6719

.. .8 .0315 9/64 .. .1406 L .. .2900 11/16 .. .6875

67 .. .0320 27 .. .1440 M .. .2950 45/64 .. .7031

66 .. .0330 26 . .1470 19/64 .. .2969 .. 18. .7087

65 .. .0350 25 .. .1495 N .. .3020 23/32 .. .7187

. .9 .0354 24 .. .1520 5/16 .. .3125 47/64 .. .7344

64 .. .0360 23 .. .1540 .. 8. .3150 .. 19. .7480

63 .. .0370 5/32 . .1562 O .. .3160 3/4 .. .7500

62 .. .0380 22 .. .1570 P .. .3230 49/64 .. .7656

61 .. .0390 .. 4. .1575 21/64 .. .3281 25/32 .. .7812

.. 1. .0394 21 .. .1590 Q .. .3320 .. 20. .7874

60 .. .0400 20 .. .1610 R .. .3390 51/64 .. .7969

59 .. .0410 19 .. .1660 11/32 .. .3437 13/16 .. .8125

58 .. .0420 18 . .1695 S .. .3480 .. 21. .8268

57 . .0430 11/64 .. .1719 .. 9. .3543 53/64 .. .8281

56 .. .0465 17 .. .1730 T .. .3580 27/32 .. .84373/64 .. .0469 16 .. .1770 23/64 .. .3594 55/64 .. .8594

55 .. .0520 15 .. .1800 U .. .3680 .. 22. .8661

54 .. .0550 14 .. .1820 3/8 .. .3750 7/8 .. .8750

53 .. .0595 13 .. .1850 V .3770 57/64 .. .8906

1/16 . .0625 3/16 .. .1875 W .. .3860 .. 23. .9055

52 .. .0635 12 .. .1890 25/64 .. .3906 29/32 .. .9062

51 .. .0670 11 .. .1910 .. 10. .3937 59/64 .. .9219

50 .. .0700 10 .. .1935 X .. .3970 15/16 .. .9375

49 . .0730 9 .. .1960 Y . .4040 .. 24. .9449

48 .. .0760 .. 5. .1968 13/32 .. .4062 61/64 .. .9531

5/64 .. .0781 8 .. .1990 Z .. .4130 31/32 .. .9687

47 .. .0785 7 .. .2010 27/64 .. .4219 .. 25. .9842

.. 2. .0787 13/64 .. .2031 .. 11. .4331 63/64 .. .9844

46 .. .0810 6 .. .2040 1 25.4 1.000

Web sights that can answer most of the design, detailing and manufacturing questionsyou may have.

www.matweb.com material properties

www.engineersedge.com all engineering (mechanical, mfg., chem., MAE, Indus.)

www.draftingzone.com any detailing or dimensioning questions

www.howstuffworks.com right. How stuff works! Anything!

http://web.mit.edu/2.670/www/Tutorials/Machining/Description.html manufacturing

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Thread

Size

Drill

Diameter

(in)

Tap Drill

Size

Thread

Size

Drill

Diameter

(in)

Tap Drill

Size

- SAE Tap & Drill Chart - Fine Thread

.0595 No. 53 0-80 .0469 3/64

2-56 .0700 No. 50 1-72 .0595 No. 53

3-48 .0785 No. 47 2-64 .0700 No. 50

4-40 .0890 No. 43 3-56 .0820 No. 45

5-40 .1015 No. 38 4-48 .0935 No. 42

6-32 .1065 No. 36 5-44 .1040 No. 37

8-32 .1360 No. 29 6-40 .1130 No. 33

10-24 .1495 No. 25 8-36 .1360 No. 29

12-24 .1770 No. 16 10-32 .1590 No. 21

1/4-20 .2010 No. 7 12-28 .1820 No. 14

5/16-18 .2570 'F' 1/4-28 .2130 No. 3

3/8-16 .3125 5/16 5/16-24 .2720 'I'

7/16-14 .3680 'U' 3/8-24 .3320 'Q'

1/2-13 .4219 27/64 7/16-20 .3906 25/64

9/16-12 .4844 31/64 1/2-20 .4531 29/64

5/8-11 .5312 17/32 9/16-18 .5156 33/64

3/4-10 .6562 21/32 5/8-18 .5781 37/64

7/8-9 .7656 49/64 3/4-16 .6875 11/16

1"-8 .8750 7/8 7/8-14 .8125 13/16

1"-14 .9375 59/64

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asu design and manufacturing booklet

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