critical manufacturing understandings
TRANSCRIPT
Critical Manufacturing Understandings
(Steel)
Presented by: Thomas Turner
T And T LLC
Introduction and Travel Agenda
9:00AM-9:30AM Introduction
9:30AM-10:00AM Travel Time to Experimetal
10:00AM-11:30AM Tour and final questions
11:30AM – 12:00PM Lunch
12:00PM-12:30PM Travel To Iroquois
1:00PM-2:00PM Tour and final questions
2:00PM-2:30PM Travel back to Auburn Hills
2:30PM-5:00PM Presentation
Agenda
• Costing of Dies, labor and various materials• Primary Forming operations• Trimming operations• Hemming operations• Welding Operations• Fixture Operations• Tooling Costs• Materials• Plant Layouts• Plant Visits
Costing of Dies, labor and various materials
• Costs for the following:• Stamping dies
– How does this differ when dealing with stamping HSS vs. carbon steel vs. aluminum sheet• Stamping presses (typical for body panels)• Labor – understanding how much labor is needed to run a presses and other equipment
Die cost estimating is based on the following principles:
Size and class of the part S/M/L = Per die 5-10K/15-25K/25-300K (+additional actions)
Type of material- HSLA – Forms well and has great stretchHSS-Spring back problems and can’t pierceAl-Less bending abilityBoron-Forms well but must be laser cut
Stamping process-HSLA-Blank, Form, Trim, ShipHSS- Blank, Form, Re-strike, Trim, shipAl- Blank, Form, Reform, Re-strike, ShipBoron- Hot form, laser trim Ship
Die Processing Steps
• Paper blank and paper process
• Establish directions of forming
• Establish directions of piercingLine or Transfer Progressive
Aluminum and HSS may require a re-strike die to set
bend formations. Over-bending by as much as 20º.
This would add one more station and the need for adjustment on the small
flanges.
GD&T could also change hole pierce operation to a post
bend operation.
Typical Stamping Press information
USED 150 TON HEIM STRAIGHT SIDE DOUBLE CRANK PRESS NEW 1980
150 Ton, Johnson #G2-150, Gap Frame, 6" str., 60" x 24" bed, 17" SH, 40 SPM, air cl. (#18430)
How many tons and do they match your FEA
predictions!
Stroke if the total open shut distance. Does this match your die and can you get
the part out once its formed?
Does my die fit?Shut Height from bottom bed to top
plate.
Does my die fit?
Strokes per minute. With 80% uptime rate. Does this
meet my volume requirements.
Types of presses
• 5-50 Tons
• 70-150 Ton• 150-1200Ton
Body Panel Forming• Most body panels are stretch formed on a three or four piece die. Below is a typical die shape
with function described. Press bed and tonnage requirements will have to be determined by simulation and die design.
Post
Step #1
Post
Step #2
Post
Step #3
Hot Stamping
Post
One Step forming Oven
Laser
Press labor
• Labor is either direct or indirect.• Direct labor workers load and unload parts• Indirect labor is support –forklift drivers, washers, quality control.
• US labor cost is $65/hour while Asia cost is less than $36/hour.
• Labor is determined by parts per hour. 65 parts and hour made by one US worker costs 1$ per part in labor.
• To this you must add machine rates of presses and lasers at 100-200/Hour USD.
Thus a labor cost for a three man press operation = 3X65$ + Press rateParts per hour
Types of Materials• AUTOMOTIVE STEEL SURVEY PRODUCT GROUP DEFINITIONS• Carbon Grades• These are products generally purchased to chemistry (usually carbon level). The category includes the following:• Formability grades, such as CS, FS, DS, DDS & EDDS.• Chemistry grades such as SAE 1005 through SAE 1095. These grades are not guaranteed to meet mechanical properties. • Bake Hard • These are products specified with a strength increase requirement after an aging treatment. The category includes the following:• All grades classified as Bake Hard or Dent Resistant regardless of Yield Strength guarantees.• Medium Strength Steel Grades (>180 MPa min to <=340 MPa min YS or >270 MPa min to <=440 MPA min TS)• These are products at more than “180 MPa minimum” up to “340 MPa minimum” when yield strength is the primary identifier, or at more than “270 MPa minimum” up to
“440 MPa minimum” when tensile strength is the primary identifier. The category includes the following grades identifiers that fall within the specified mechanical property range:
• High Strength Low Alloy (HSLA) • Structural Steel (SS)• Solution Hardened Steel (SHS)• Conventional High Strength Steel Grades (>340 MPa min YS or >440 MPa min TS)• These are products at more than “340 MPa minimum” when yield strength is the primary identifier, or more than “440 MPa minimum” when tensile strength is the primary
identifier. The category includes the following grades identifiers that fall within the specified mechanical property range:• HSLA• SS • SHS• Recovery Anneal (RA)• Advanced High Strength Steel Grades (AHSS) Dual Phase• These are high strength products that provide enhanced specified properties such as ductility or flangeability at the specified high strength level and are ordered with the
“Dual Phase” specification. Dual Phase steel defined as those that exhibit a “Dual Phase” (martensite and ferrite) microstructure, regardless of guaranteed minimum (Yield or Tensile) Strength.
• Advanced High Strength Steel non-Dual Phase Grades• These are advanced high strength steel products that are not ordered to the Dual Phase specification. This category includes the following:• Transformation Indusced Plasticity (TRIP)• Complex Phase (CP)• Martensitic (MS)• Twinning Induced Plasticity (TWIP)• Heat treatable Boron Bearing Steel• High Hole Expansion (HHE)• Stretch Flangable (SF)
Primary Forming operations• Primary Fabrication Forming:
• What are the typical forming operations (drawing, striking, flanging, etc)?
• What is transfer press stamping?
• What is brake forming?
• What is press line stamping?
The Following Die Related details will be covered in the following slides• Draw
• Re-strike
• Bending
• Cam Form/Cam Pierce
• Roll-forming
• Conical Issues
• Transfer – Progressive- Line dies – NC punching- NC bending
Draw Die
Post
Cavity
PunchLower
Binder
Upper
Binder
Re-Strike Die
Post
Cavity
PunchLower
Binder
Upper
Binder
Draw Shape
Final Form
or
Re-Strike Shape
Bending
Punch
Pad Flange Steel
Die Bend Press-Break Bend
CNC Punching / BendingThis is the type of manufacturing that applies mostly to commercial items. The Numerical Controlled
Punching Equipment is fast, repeatable, and easy to interact with.
CNC Punch Press Break Press
CAM Forming/Piercing
• Note-
• Piercing in the direction fo the main press stroke will cost 1.5-3K per hole. A Cam Pierced hole or formation can cost 25-30K on a medium sized die.
Roll Forming
Flying Punch Weld / Cutoff
Conical Issues
Higher strength steels have a harder time producing a conical shape that can be tapped. This creates the need for additional fasteners and increases your cost. This is to be considered when “thrifting” products
Die Definitions
• Line Die- – Larger panels– Class A– 500+ Tons per die (total tonnage greater than transfer press line)– No Carrier strip – Not necessarily run in line
• Transfer Die-– Medium to small stampings– Class A&B– Total tonnage of all dies considered– No Carrier Strip
• Progressive Die– Small to medium size stampings– Class B– Total tonnage of all dies considered– Carrier Strip
Trimming operations• Trimming:• What are the different types of trimming operations and when are they used in the process?• What equipment is used for trimming?
Punch Press• No fixture required• Available world wide• Machine cost 100$/Hr • One operator• Very competitively bid• 180 Hits per minute
Laser• Fixture required• Available world wide• Machine cost 125$/Hr • One operator/share if Inches per hour allow.• Very competitively bid• 50-500 Inches per minute, Stacking possible
Die Trimming• Part of Die process• Trim Steels are like flange steels with less clearance
Hemming operations
• Hemming:
• Explain the process of hemming
• What equipment is needed for hemming?
Hemming is a 180° flange that is more like folding than any other process. The corners are relived in a flanging process to allow compression and aid in areas of stretch. This relief is relative to length of line. Length of line is the starting length of metal before bending, stretching, or compression.
A classic example of hemming can be seen in car doors. The auto industry uses both die and fixture held hemming techniques. In the following slides we will look at each of these processes
Die Hemming
45º
90º
Roller Hemming
Roll hemming is done with a robot and usually makes three passes. The start and stop of these passes greatly affect the shape of the hemmed surface
Hemming Equipment
Welding Operations• Welding:• Explain the different types of welding and when they are used • What are the limitations with the different types of welding?
• MIG stands for Metal Inert Gas Welding. This is often referred to as wire-feed welding and is used in most manufacturing industries. The welding equipment is available world wide and a worker can be trained relatively quickly. This welding process does impart allot of heat into the base materials. Controlling the heat and the resulting part twist is the “trick” to utilizing MIG welding in your process. The heat is controlled through the use of chiller blocks and optimizing the weld process.
• TIG is short for Gas Tungsten Arc Welding (GTAW). In the TIG welding process, an arc is formed between a non-consumable tungsten electrode and the metal being welded. The welding equipment is available world wide but a worker can not be trained quickly to use this equipment. This welding process does not impart allot of heat into the base materials but is labor intensive and costly to use. This process is best used on low volume and lighter gage materials.
• Arc welding uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and/or an evaporating filler material. The process of arc welding is widely used because of its low capital and running costs.
• Spot welding is a type of resistance welding used to weld various sheet metals. Typically the sheets are in the 0.5-3.0 mm thickness range. The process uses two shaped copper alloy electrodes to concentrate welding current and force between the materials to be welded. The result is a small "spot" that is quickly heated to the melting point, this forms a nugget of welded metal after the current is removed.
• Laser beam welding (LBW) is a welding technique used to join multiple pieces of metal through the use of a laser. The beam provides a concentrated heat source, allowing for narrow, deep welds and high welding rates. The process is frequently used in high volume applications, such as in the automotive industry.
Fixture Operations• Fixtures:
• Explain what type of fixtures are needed for welding (cost, complexity)
• Welding fixture types are dependent on the material and yearly volume of the product. Exhaust systems have very elaborate gage systems that mask process variations and are fairly complicated to manufacture. In prototype they use a very simple and inexpensive process that I will cover in class.
• Welding fixtures must account for the variation of the detail parts and orient them to yield a “good” finished product.
• These fixtures can cost 4-5K without clamps or adjustability to many thousand of dollars for large welded items like truck frames.
– Low cost are laser cut egg crates
– Medium cost are NC cut High density foam with installed clamps
– High cost will be full production elements with an associated development process.
Tooling Costs• Tooling:• Tooling costs (based on part size and complexity)• How do stamping dies differ for different materials (is a harder die needed to stamp HSS vs. low carbon steel, for example?)
• Steel part cost is generated through the following steps:– Establish weight of the blank. Thickness X Length X Width X .283 = Lbs of
steel– Multiply this steel weight by the cost of the steel you are using. If you don’t know
Guess at 35-45 cents a pound. – The material cost represents 10% of the total cost for low Volume parts and as
much as 60% for high volume parts.– The part costs is greatly affected by the tooling cost. The tooling is usually
amortized over the volume and years that the part is going to be made.Tooling cost is generated through he following steps:– Define number of processes – Assign costs to each process Per die 5-10K small/15-25K medium /25-300K
large.– Each process represents a machine cost and man divided by pieces per hour.– Validate through Comparative Analysis or send quotes out for bid
Materials
Materials:What are issues/limitations with forming materials such as HSS and aluminum
Field class questions relative to these materials.
Plant Layouts• Plant layout:
• Need to understand the material flow through the plant from roles of steel to finished part
• Floor space required for presses and inventory
Process flow through a plant:
• Material Received
•Thickness and material type validated through incoming inspection procedures. Once approved, the material is labeled and stored until needed.
• Material is delivered to the press.
• In process inspection procedure to validate that the material is the right material.
• Last part/first part inspection is conducted
• Hourly or by number parts are checked.
• Parts are final inspected and shipped.
Latest trend is to look at supply chain Miles.
Plant Visits• The objectives of the plant visits are as follows:• See stamping operations first hand• Gain an understanding of the size of the presses• Understand how material flows through a plant• How is inventory handled• See secondary operations first hand (trimming, welding, hole punching, etc)
